Top 20 NuGet collections Packages

Injects new collection classes to the standard system namespace.
This library provides comprehensive observable Collection/List/Dictionary. Interfaces (Icollection, IList, etc) are also implemented and trigger INotifyCollectionChanged. The library includes utility collections such as a ObservableListAdapter which can syncronize two lists of different, but related...
An alternative to System.Collection.Generics.LinkedList with reverse operation and enumeration without allocation.
Useful IEnumerable extension methods.
It's a set of factory methods such as ListOf(1, 2) or ListOf/<int />() to create the basic generic collections. Package was inspired by Kotlin language.
Provides the ability to more intuitively connect Parent-Child relationships via Callback methods.
Provides numerous graph theory based Graph Collections
Package Description
Library of sparse collections and tools for working with them.
Provides a set of features making it possible to emulate C++ Variants for dotnet.
Provides robust map collections for C# with high compatibility with core collection interfaces, including BiMap, MultiMap and MultiBiMap.
The SparseCollections library provides the SparseArray<T> and SparseMatrix<T> collection classes. The array class allow statements such as "array[1000000] = 5" or "array[-1000000] = 6" without having to create a large array. The matrix class does the same thing using a two-dimensional-array metaphor...
This package contains a library of upcastable lists/list wrappers that implement the observable pattern, invoking events when a list is modified, and a set of list bindings that synchronize the content of observable lists using a mapping between item types.
PSyCEX.NET components
One<T> is a generic collection that contains exactly one item. This kind of generic collection allows you to use LINQ expression to write closures and functional programming.
A small evaluation tool to calculate the jaccard similarity index and distance. It also includes mean jaccard index and distance which considers the order of the elements as well.
Provides a Set Collection implementation.