diff --git a/include/picongpu/particles/Manipulate.hpp b/include/picongpu/particles/Manipulate.hpp
index fef2a88a150..ea5ebf13713 100644
--- a/include/picongpu/particles/Manipulate.hpp
+++ b/include/picongpu/particles/Manipulate.hpp
@@ -134,7 +134,7 @@ namespace picongpu
             uint32_t T_area = CORE + BORDER>
         inline void manipulate(uint32_t const currentStep)
         {
-            using SpeciesSeq = typename pmacc::ToSeq<T_Species>::type;
+            using SpeciesSeq = pmacc::ToSeq<T_Species>;
             using Functor
                 = Manipulate<T_Manipulator, boost::mpl::_1, T_Filter, std::integral_constant<uint32_t, T_area>>;
             pmacc::meta::ForEach<SpeciesSeq, Functor> forEach;
@@ -155,7 +155,7 @@ namespace picongpu
             typename T_Filter = filter::All>
         inline void manipulate(uint32_t const currentStep, T_AreaMapperFactory const& areaMapperFactory)
         {
-            using SpeciesSeq = typename pmacc::ToSeq<T_Species>::type;
+            using SpeciesSeq = pmacc::ToSeq<T_Species>;
             using Functor = Manipulate<T_Manipulator, boost::mpl::_1, T_Filter>;
             pmacc::meta::ForEach<SpeciesSeq, Functor> forEach;
             forEach(currentStep, areaMapperFactory);
diff --git a/include/picongpu/particles/collision/Collider.hpp b/include/picongpu/particles/collision/Collider.hpp
index 6d484b6363f..2a4bbf361de 100644
--- a/include/picongpu/particles/collision/Collider.hpp
+++ b/include/picongpu/particles/collision/Collider.hpp
@@ -66,7 +66,7 @@ namespace picongpu
             {
                 void operator()(std::shared_ptr<DeviceHeap> const& deviceHeap, uint32_t currentStep)
                 {
-                    using SpeciesPairList = typename pmacc::ToSeq<typename T_Collider::SpeciesPairs>::type;
+                    using SpeciesPairList = pmacc::ToSeq<typename T_Collider::SpeciesPairs>;
                     constexpr size_t numPairs = pmacc::mp_size<SpeciesPairList>::value;
                     std::make_index_sequence<numPairs> index{};
                     detail::CallColliderForAPair<SpeciesPairList, T_Collider, colliderId>{}(
diff --git a/include/picongpu/particles/particleToGrid/ComputeGridValuePerFrame.def b/include/picongpu/particles/particleToGrid/ComputeGridValuePerFrame.def
index 2ace38cfc2a..c8545572d75 100644
--- a/include/picongpu/particles/particleToGrid/ComputeGridValuePerFrame.def
+++ b/include/picongpu/particles/particleToGrid/ComputeGridValuePerFrame.def
@@ -193,7 +193,7 @@ namespace picongpu
             struct CreateEligible
             {
                 // wrap single arguments to sequence
-                using SeqSpecies = typename pmacc::ToSeq<T_SeqSpecies>::type;
+                using SeqSpecies = pmacc::ToSeq<T_SeqSpecies>;
                 using FilteredAttribute = FilteredDerivedAttribute<T_DerivedAttribute, T_Filter>;
 
                 using type = typename traits::GenerateSolversIfSpeciesEligible<
diff --git a/include/picongpu/particles/traits/GenerateSolversIfSpeciesEligible.hpp b/include/picongpu/particles/traits/GenerateSolversIfSpeciesEligible.hpp
index 7abfe5ec7a8..89af7e7bb75 100644
--- a/include/picongpu/particles/traits/GenerateSolversIfSpeciesEligible.hpp
+++ b/include/picongpu/particles/traits/GenerateSolversIfSpeciesEligible.hpp
@@ -54,7 +54,7 @@ namespace picongpu
             struct GenerateSolversIfSpeciesEligible
             {
                 // wrap single arguments to sequence
-                using SeqSpecies = typename pmacc::ToSeq<T_SeqSpecies>::type;
+                using SeqSpecies = pmacc::ToSeq<T_SeqSpecies>;
 
                 // unspecialized solver
                 using Solver = T_Solver;
diff --git a/include/picongpu/plugins/BinEnergyParticles.hpp b/include/picongpu/plugins/BinEnergyParticles.hpp
index 6f2e9f64d67..9a4bed0b7c3 100644
--- a/include/picongpu/plugins/BinEnergyParticles.hpp
+++ b/include/picongpu/plugins/BinEnergyParticles.hpp
@@ -212,8 +212,7 @@ namespace picongpu
             // find all valid filter for the current used species
             template<typename T>
             using Op = typename particles::traits::GenerateSolversIfSpeciesEligible<T, ParticlesType>::type;
-            using EligibleFilters =
-                typename MakeSeqFromNestedSeq<pmacc::mp_transform<Op, particles::filter::AllParticleFilters>>::type;
+            using EligibleFilters = pmacc::mp_flatten<pmacc::mp_transform<Op, particles::filter::AllParticleFilters>>;
 
             //! periodicity of computing the particle energy
             plugins::multi::Option<std::string> notifyPeriod = {"period", "enable plugin [for each n-th step]"};
diff --git a/include/picongpu/plugins/Emittance.hpp b/include/picongpu/plugins/Emittance.hpp
index e2262486589..b1c1cc7fb0c 100644
--- a/include/picongpu/plugins/Emittance.hpp
+++ b/include/picongpu/plugins/Emittance.hpp
@@ -221,8 +221,7 @@ namespace picongpu
             // find all valid filter for the current used species
             template<typename T>
             using Op = typename particles::traits::GenerateSolversIfSpeciesEligible<T, ParticlesType>::type;
-            using EligibleFilters =
-                typename MakeSeqFromNestedSeq<pmacc::mp_transform<Op, particles::filter::AllParticleFilters>>::type;
+            using EligibleFilters = pmacc::mp_flatten<pmacc::mp_transform<Op, particles::filter::AllParticleFilters>>;
 
             //! periodicity of computing the particle energy
             plugins::multi::Option<std::string> notifyPeriod
diff --git a/include/picongpu/plugins/EnergyParticles.hpp b/include/picongpu/plugins/EnergyParticles.hpp
index e01099b56c2..a59b78c8877 100644
--- a/include/picongpu/plugins/EnergyParticles.hpp
+++ b/include/picongpu/plugins/EnergyParticles.hpp
@@ -178,8 +178,7 @@ namespace picongpu
             // find all valid filter for the current used species
             template<typename T>
             using Op = typename particles::traits::GenerateSolversIfSpeciesEligible<T, ParticlesType>::type;
-            using EligibleFilters =
-                typename MakeSeqFromNestedSeq<pmacc::mp_transform<Op, particles::filter::AllParticleFilters>>::type;
+            using EligibleFilters = pmacc::mp_flatten<pmacc::mp_transform<Op, particles::filter::AllParticleFilters>>;
 
             //! periodicity of computing the particle energy
             plugins::multi::Option<std::string> notifyPeriod
diff --git a/include/picongpu/plugins/PhaseSpace/PhaseSpace.hpp b/include/picongpu/plugins/PhaseSpace/PhaseSpace.hpp
index 6fe290ad5d3..bac9ce7b44e 100644
--- a/include/picongpu/plugins/PhaseSpace/PhaseSpace.hpp
+++ b/include/picongpu/plugins/PhaseSpace/PhaseSpace.hpp
@@ -71,8 +71,7 @@ namespace picongpu
             // find all valid filter for the current used species
             template<typename T>
             using Op = typename particles::traits::GenerateSolversIfSpeciesEligible<T, Species>::type;
-            using EligibleFilters =
-                typename MakeSeqFromNestedSeq<pmacc::mp_transform<Op, particles::filter::AllParticleFilters>>::type;
+            using EligibleFilters = pmacc::mp_flatten<pmacc::mp_transform<Op, particles::filter::AllParticleFilters>>;
 
             //! periodicity of computing the particle energy
             plugins::multi::Option<std::string> notifyPeriod = {"period", "notify period"};
diff --git a/include/picongpu/plugins/PluginController.hpp b/include/picongpu/plugins/PluginController.hpp
index 10333a0957a..9a3c984df67 100644
--- a/include/picongpu/plugins/PluginController.hpp
+++ b/include/picongpu/plugins/PluginController.hpp
@@ -70,7 +70,6 @@
 
 #include <pmacc/mappings/kernel/MappingDescription.hpp>
 #include <pmacc/meta/AllCombinations.hpp>
-#include <pmacc/meta/SeqToList.hpp>
 
 #include <list>
 #include <memory>
diff --git a/include/picongpu/plugins/particleCalorimeter/ParticleCalorimeter.hpp b/include/picongpu/plugins/particleCalorimeter/ParticleCalorimeter.hpp
index c9563b95a5c..98a22bbf8a2 100644
--- a/include/picongpu/plugins/particleCalorimeter/ParticleCalorimeter.hpp
+++ b/include/picongpu/plugins/particleCalorimeter/ParticleCalorimeter.hpp
@@ -405,8 +405,7 @@ namespace picongpu
             // find all valid filter for the current used species
             template<typename T>
             using Op = typename particles::traits::GenerateSolversIfSpeciesEligible<T, ParticlesType>::type;
-            using EligibleFilters =
-                typename MakeSeqFromNestedSeq<pmacc::mp_transform<Op, particles::filter::AllParticleFilters>>::type;
+            using EligibleFilters = pmacc::mp_flatten<pmacc::mp_transform<Op, particles::filter::AllParticleFilters>>;
 
             //! periodicity of computing the particle energy
             plugins::multi::Option<std::string> notifyPeriod = {"period", "enable plugin [for each n-th step]"};
diff --git a/include/pmacc/meta/ForEach.hpp b/include/pmacc/meta/ForEach.hpp
index 329d660a8ef..ef9e26b65c2 100644
--- a/include/pmacc/meta/ForEach.hpp
+++ b/include/pmacc/meta/ForEach.hpp
@@ -21,7 +21,6 @@
 
 #pragma once
 
-#include "pmacc/meta/SeqToList.hpp"
 #include "pmacc/meta/accessors/Identity.hpp"
 
 #include <boost/mpl/apply.hpp>
@@ -32,7 +31,7 @@ namespace pmacc::meta
 {
     /** Compile-Time for each for Boost::MPL Type Lists
      *
-     *  @tparam T_MPLSeq A mpl sequence that can be accessed by mpl::begin, mpl::end, mpl::next
+     *  @tparam List An mp_list.
      *  @tparam T_Functor An unary lambda functor with a HDINLINE void operator()(...) method
      *          _1 is substituted by Accessor's result using boost::mpl::apply with elements from T_MPLSeq.
      *          The maximum number of parameters for the operator() is limited by
@@ -40,21 +39,19 @@ namespace pmacc::meta
      *  @tparam T_Accessor An unary lambda operation
      *
      * Example:
-     *      MPLSeq = pmacc::mp_list<int,float>
+         *      List = pmacc::mp_list<int,float>
      *      Functor = any unary lambda functor
      *      Accessor = lambda operation identity
      *
      *      definition: F(X) means boost::apply<F,X>
      *
-     *      call:   ForEach<MPLSeq,Functor,Accessor>()(42);
+         *      call:   ForEach<List,Functor,Accessor>()(42);
      *      unrolled code: Functor(Accessor(int))(42);
      *                     Functor(Accessor(float))(42);
      */
-    template<typename T_MPLSeq, typename T_Functor, typename T_Accessor = meta::accessors::Identity<>>
+        template<typename List, typename T_Functor, typename T_Accessor = meta::accessors::Identity<>>
     struct ForEach
     {
-        using List = detail::SeqToList<T_MPLSeq>;
-
         template<typename X>
         using ReplacePlaceholder =
             typename boost::mpl::apply1<T_Functor, typename boost::mpl::apply1<T_Accessor, X>::type>::type;
diff --git a/include/pmacc/meta/SeqToList.hpp b/include/pmacc/meta/SeqToList.hpp
deleted file mode 100644
index 3491f14c9ca..00000000000
--- a/include/pmacc/meta/SeqToList.hpp
+++ /dev/null
@@ -1,38 +0,0 @@
-/* Copyright 2013-2022 Rene Widera, Bernhard Manfred Gruber
- *
- * This file is part of PMacc.
- *
- * PMacc is free software: you can redistribute it and/or modify
- * it under the terms of either the GNU General Public License or
- * the GNU Lesser General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * PMacc is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License and the GNU Lesser General Public License
- * for more details.
- *
- * You should have received a copy of the GNU General Public License
- * and the GNU Lesser General Public License along with PMacc.
- * If not, see <http://www.gnu.org/licenses/>.
- */
-
-#pragma once
-
-#include "Mp11.hpp"
-
-#include <boost/mpl/copy.hpp>
-
-namespace pmacc
-{
-    namespace meta
-    {
-        namespace detail
-        {
-            template<typename Seq>
-            using SeqToList = typename boost::mpl::copy<Seq, boost::mpl::back_inserter<mp_list<>>>::type;
-        } // namespace detail
-    } // namespace meta
-} // namespace pmacc
diff --git a/include/pmacc/meta/conversion/MakeSeq.hpp b/include/pmacc/meta/conversion/MakeSeq.hpp
index 908712a52c4..c385df49fad 100644
--- a/include/pmacc/meta/conversion/MakeSeq.hpp
+++ b/include/pmacc/meta/conversion/MakeSeq.hpp
@@ -1,4 +1,4 @@
-/* Copyright 2013-2022 Rene Widera
+/* Copyright 2013-2022 Rene Widera, Bernhard Manfred Gruber
  *
  * This file is part of PMacc.
  *
@@ -22,12 +22,12 @@
 
 #pragma once
 
-#include "pmacc/meta/conversion/MakeSeqFromNestedSeq.hpp"
+#include "pmacc/meta/Mp11.hpp"
 
 namespace pmacc
 {
-    /** short hand definition for @see MakeSeqFromNestedSeq<> */
+    /** Makes an mp_list from T_Args. If any type in T_Args is a list itself, it will be unwrapped.
+     */
     template<typename... T_Args>
-    using MakeSeq_t = typename MakeSeqFromNestedSeq<mp_list<T_Args...>>::type;
-
+    using MakeSeq_t = mp_flatten<mp_list<T_Args...>>;
 } // namespace pmacc
diff --git a/include/pmacc/meta/conversion/MakeSeqFromNestedSeq.hpp b/include/pmacc/meta/conversion/MakeSeqFromNestedSeq.hpp
deleted file mode 100644
index 70856a68b37..00000000000
--- a/include/pmacc/meta/conversion/MakeSeqFromNestedSeq.hpp
+++ /dev/null
@@ -1,43 +0,0 @@
-/* Copyright 2013-2022 Rene Widera
- *
- * This file is part of PMacc.
- *
- * PMacc is free software: you can redistribute it and/or modify
- * it under the terms of either the GNU General Public License or
- * the GNU Lesser General Public License as published by
- * the Free Software Foundation, either version 3 of the License, or
- * (at your option) any later version.
- *
- * PMacc is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
- * GNU General Public License and the GNU Lesser General Public License
- * for more details.
- *
- * You should have received a copy of the GNU General Public License
- * and the GNU Lesser General Public License along with PMacc.
- * If not, see <http://www.gnu.org/licenses/>.
- */
-
-
-#pragma once
-
-#include "pmacc/meta/Mp11.hpp"
-#include "pmacc/meta/conversion/ToSeq.hpp"
-
-namespace pmacc
-{
-    /** combine all elements of the input type to a single vector
-     *
-     * If elements of the input sequence are a sequence themself, all of their
-     * elements will be added to the resulting sequence
-     *
-     * @tparam T_In a boost mpl sequence or single type
-     */
-    template<typename T_In>
-    struct MakeSeqFromNestedSeq
-    {
-        using type = mp_flatten<typename ToSeq<T_In>::type>;
-    };
-
-} // namespace pmacc
diff --git a/include/pmacc/meta/conversion/SeqToMap.hpp b/include/pmacc/meta/conversion/SeqToMap.hpp
index 193d3667fac..0cb8cd2d952 100644
--- a/include/pmacc/meta/conversion/SeqToMap.hpp
+++ b/include/pmacc/meta/conversion/SeqToMap.hpp
@@ -21,7 +21,6 @@
 
 #pragma once
 
-#include "pmacc/meta/SeqToList.hpp"
 #include "pmacc/meta/accessors/Identity.hpp"
 #include "pmacc/types.hpp"
 
@@ -29,23 +28,23 @@
 
 namespace pmacc
 {
-    /** convert boost mp11 list to a map
+    /** convert a list to a map
      *
-     * @tparam T_MPLSeq any boost mp11 list
+     * @tparam T_List an mp_list.
      * @tparam T_UnaryOperator unary operator to translate type from the sequence
      * to a mpl pair
      * @tparam T_Accessor An unary lambda operator which is used before the type
      * from the sequence is passed to T_UnaryOperator
      * @return ::type mpl map
      */
-    template<typename T_MPLSeq, typename T_UnaryOperator, typename T_Accessor = meta::accessors::Identity<>>
+    template<typename T_List, typename T_UnaryOperator, typename T_Accessor = meta::accessors::Identity<>>
     struct SeqToMap
     {
         template<typename X>
         using Op =
             typename boost::mpl::apply1<T_UnaryOperator, typename boost::mpl::apply1<T_Accessor, X>::type>::type;
 
-        using ListOfTuples = mp_transform<Op, meta::detail::SeqToList<T_MPLSeq>>;
+        using ListOfTuples = mp_transform<Op, T_List>;
         using type = mp_fold<ListOfTuples, mp_list<>, mp_map_insert>;
     };
 } // namespace pmacc
diff --git a/include/pmacc/meta/conversion/ToSeq.hpp b/include/pmacc/meta/conversion/ToSeq.hpp
index 65cebee6717..0f6a70d5489 100644
--- a/include/pmacc/meta/conversion/ToSeq.hpp
+++ b/include/pmacc/meta/conversion/ToSeq.hpp
@@ -21,23 +21,27 @@
 
 #pragma once
 
-#include "pmacc/types.hpp"
+#include "pmacc/meta/Mp11.hpp"
 
 namespace pmacc
 {
-    /** cast type to boost mpl vector
-     * @return ::type if T_Type is sequence then identity of T_Type
-     *                else mp_list<T_Type>
-     */
-    template<typename T_Type>
-    struct ToSeq
+    namespace detail
     {
-        using type = mp_list<T_Type>;
-    };
+        template<typename T_Type>
+        struct ToSeq
+        {
+            using type = mp_list<T_Type>;
+        };
 
-    template<typename... Ts>
-    struct ToSeq<mp_list<Ts...>>
-    {
-        using type = mp_list<Ts...>;
-    };
+        template<typename... Ts>
+        struct ToSeq<mp_list<Ts...>>
+        {
+            using type = mp_list<Ts...>;
+        };
+    } // namespace detail
+
+    /** If T_Type is an mp_list, return it. Otherwise wrap it in an mp_list.
+     */
+    template<typename T_Type>
+    using ToSeq = typename detail::ToSeq<T_Type>::type;
 } // namespace pmacc
diff --git a/include/pmacc/particles/ParticleDescription.hpp b/include/pmacc/particles/ParticleDescription.hpp
index 716660d4838..9c176dd5956 100644
--- a/include/pmacc/particles/ParticleDescription.hpp
+++ b/include/pmacc/particles/ParticleDescription.hpp
@@ -63,11 +63,11 @@ namespace pmacc
     {
         using Name = T_Name;
         using SuperCellSize = T_SuperCellSize;
-        using ValueTypeSeq = typename ToSeq<T_ValueTypeSeq>::type;
-        using FlagsList = typename ToSeq<T_Flags>::type;
+        using ValueTypeSeq = ToSeq<T_ValueTypeSeq>;
+        using FlagsList = ToSeq<T_Flags>;
         using HandleGuardRegion = T_HandleGuardRegion;
-        using MethodsList = typename ToSeq<T_MethodsList>::type;
-        using FrameExtensionList = typename ToSeq<T_FrameExtensionList>::type;
+        using MethodsList = ToSeq<T_MethodsList>;
+        using FrameExtensionList = ToSeq<T_FrameExtensionList>;
         using ThisType = ParticleDescription<
             Name,
             SuperCellSize,
@@ -100,7 +100,7 @@ namespace pmacc
         using type = ParticleDescription<
             typename OldParticleDescription::Name,
             typename OldParticleDescription::SuperCellSize,
-            typename ToSeq<T_NewValueTypeSeq>::type,
+            ToSeq<T_NewValueTypeSeq>,
             typename OldParticleDescription::FlagsList,
             typename OldParticleDescription::HandleGuardRegion,
             typename OldParticleDescription::MethodsList,
@@ -124,7 +124,7 @@ namespace pmacc
             typename OldParticleDescription::FlagsList,
             typename OldParticleDescription::HandleGuardRegion,
             typename OldParticleDescription::MethodsList,
-            typename ToSeq<T_FrameExtensionSeq>::type>;
+            ToSeq<T_FrameExtensionSeq>>;
     };
 
 } // namespace pmacc
diff --git a/include/pmacc/particles/operations/Deselect.hpp b/include/pmacc/particles/operations/Deselect.hpp
index d8a01a20d4a..87f101041ab 100644
--- a/include/pmacc/particles/operations/Deselect.hpp
+++ b/include/pmacc/particles/operations/Deselect.hpp
@@ -46,7 +46,7 @@ namespace pmacc
             template<typename T_Exclude, typename T_Object>
             HDINLINE decltype(auto) deselect(T_Object& object)
             {
-                using DeselectSeq = typename ToSeq<T_Exclude>::type;
+                using DeselectSeq = ToSeq<T_Exclude>;
                 using BaseType = detail::Deselect<DeselectSeq, T_Object>;
 
                 return BaseType()(object);