ImmutableDictionary`2 Represents an immutable, unordered collection of keys and values. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableHashSet`1 Represents an immutable, unordered hash set. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableList`1 Represents an immutable list, which is a strongly typed list of objects that can be accessed by index. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableQueue`1 Represents an immutable queue. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableSortedDictionary`2 Represents an immutable sorted dictionary. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableSortedSet`1 Represents an immutable sorted set implementation. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableStack`1 Represents an immutable stack. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableArray`1 Represents an array that is immutable; meaning it cannot be changed once it is created. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableArray Provides methods for creating an array that is immutable; meaning it cannot be changed once it is created. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableDictionary Provides a set of initialization methods for instances of the class. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableHashSet Provides a set of initialization methods for instances of the class. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableInterlocked Contains interlocked exchange mechanisms for immutable collections. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableList Provides a set of initialization methods for instances of the class. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableQueue Provides a set of initialization methods for instances of the class. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableSortedDictionary Provides a set of initialization methods for instances of the class. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableSortedSet Provides a set of initialization methods for instances of the class. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 ImmutableStack Provides a set of initialization methods for instances of the class. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 IImmutableDictionary`2 Represents an immutable collection of key/value pairs. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 IImmutableList`1 Represents a list of elements that cannot be modified. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 IImmutableQueue`1 Represents an immutable first-in, first-out collection of objects. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 IImmutableSet`1 Represents a set of elements that can only be modified by creating a new instance of the set. NuGet package: System.Collections.Immutable (about immutable collections and how to install)

 IImmutableStack`1 Represents an immutable last-in-first-out (LIFO) collection. NuGet package: System.Collections.Immutable (about immutable collections and how to install)