System.CodeDom by: Microsoft

Provides types that can be used to model the structure of a source code document and to output source code for that model in C# or Visual Basic.

System.Collections by: Microsoft

Provides classes that define generic collections, which allow developers to create strongly typed collections that provide better type safety and performance than non-generic strongly typed collections. Commonly Used Types: System.Collections.Generic.List<T> System.Collections.Generic.Dictionary<TKey, TValue> System.Collections.Generic.Queue<T> System.Collections.Generic.Stack<T> System.Collections.Generic.HashSet<T> System.Collections.Generic.LinkedList<T> System.Collections.Generic.EqualityComparer<T> System.Collections.Generic.Comparer<T> System.Collections.Generic.SortedDictionary<TKey, TValue>

System.Collections.Concurrent by: Microsoft

Provides several thread-safe collection classes that should be used in place of the corresponding types in the System.Collections.NonGeneric and System.Collections packages whenever multiple threads are accessing the collection concurrently. Commonly Used Types: System.Collections.Concurrent.ConcurrentDictionary<TKey, TValue> System.Collections.Concurrent.ConcurrentQueue<T> System.Collections.Concurrent.ConcurrentBag<T> System.Collections.Concurrent.BlockingCollection<T> System.Collections.Concurrent.ConcurrentStack<T> When using NuGet 3.x this package requires at least version 3.4.

System.Collections.Immutable by: Microsoft

This package provides collections that are thread safe and guaranteed to never change their contents, also known as immutable collections. Like strings, any methods that perform modifications will not change the existing instance but instead return a new instance. For efficiency reasons, the implementation uses a sharing mechanism to ensure that newly created instances share as much data as possible with the previous instance while ensuring that operations have a predictable time complexity. The System.Collections.Immutable library is built-in as part of the shared framework in .NET Runtime. The package can be installed when you need to use it in other target frameworks.

System.Collections.NonGeneric by: Microsoft

Provides classes that define older non-generic collections of objects, such as lists, queues, hash tables and dictionaries. Developers should prefer the generic collections in the System.Collections package. Commonly Used Types: System.Collections.ArrayList System.Collections.Hashtable System.Collections.CollectionBase System.Collections.ReadOnlyCollectionBase System.Collections.Stack System.Collections.SortedList System.Collections.DictionaryBase System.Collections.Queue System.Collections.Comparer System.Collections.CaseInsensitiveComparer When using NuGet 3.x this package requires at least version 3.4.

System.Collections.Sequences by: Microsoft Corporation

Non-allocating collections

System.Collections.Specialized by: Microsoft

Provides older specialized non-generic collections; for example, a linked list dictionary, a bit vector, and collections that contain only strings. Commonly Used Types: System.Collections.Specialized.NameValueCollection System.Collections.Specialized.NameObjectCollectionBase System.Collections.Specialized.StringCollection System.Collections.Specialized.IOrderedDictionary System.Collections.Specialized.HybridDictionary System.Collections.Specialized.OrderedDictionary System.Collections.Specialized.ListDictionary System.Collections.Specialized.StringDictionary System.Collections.Specialized.BitVector32 When using NuGet 3.x this package requires at least version 3.4.

System.ComponentModel by: Microsoft

Provides interfaces for the editing and change tracking of objects used as data sources. Commonly Used Types: System.ComponentModel.CancelEventArgs System.IServiceProvider System.ComponentModel.IEditableObject System.ComponentModel.IChangeTracking System.ComponentModel.IRevertibleChangeTracking When using NuGet 3.x this package requires at least version 3.4.

System.ComponentModel.Annotations by: Microsoft

Provides attributes that are used to define metadata for objects used as data sources. Commonly Used Types: System.ComponentModel.DataAnnotations.ValidationResult System.ComponentModel.DataAnnotations.IValidatableObject System.ComponentModel.DataAnnotations.ValidationAttribute System.ComponentModel.DataAnnotations.RequiredAttribute System.ComponentModel.DataAnnotations.StringLengthAttribute System.ComponentModel.DataAnnotations.DisplayAttribute System.ComponentModel.DataAnnotations.RegularExpressionAttribute System.ComponentModel.DataAnnotations.DataTypeAttribute System.ComponentModel.DataAnnotations.RangeAttribute System.ComponentModel.DataAnnotations.KeyAttribute

System.ComponentModel.EventBasedAsync by: Microsoft

Provides support classes and delegates for the event-based asynchronous pattern. Developers should prefer the classes in the System.Threading.Tasks package. Commonly Used Types: System.ComponentModel.AsyncCompletedEventArgs System.ComponentModel.AsyncCompletedEventHandler System.ComponentModel.ProgressChangedEventArgs System.ComponentModel.ProgressChangedEventHandler System.ComponentModel.AsyncOperation System.ComponentModel.AsyncOperationManager When using NuGet 3.x this package requires at least version 3.4.

System.ComponentModel.Primitives by: Microsoft

Provides interfaces that are used to implement the run-time and design-time behavior of components. Commonly Used Types: System.ComponentModel.IComponent System.ComponentModel.IContainer System.ComponentModel.ISite System.ComponentModel.ComponentCollection When using NuGet 3.x this package requires at least version 3.4.

System.ComponentModel.TypeConverter by: Microsoft

Provides the System.ComponentModel.TypeConverter class, which represents a unified way of converting types of values to other types. Commonly Used Types: System.ComponentModel.TypeConverter System.ComponentModel.TypeConverterAttribute System.ComponentModel.PropertyDescriptor System.ComponentModel.StringConverter System.ComponentModel.ITypeDescriptorContext System.ComponentModel.EnumConverter System.ComponentModel.TypeDescriptor System.ComponentModel.Int32Converter System.ComponentModel.BooleanConverter System.ComponentModel.DoubleConverter When using NuGet 3.x this package requires at least version 3.4.

System.Composition by: Microsoft

Provides a version of the Managed Extensibility Framework (MEF) that is lightweight and specifically optimized for high throughput scenarios, such as the web.

System.Composition.AttributedModel by: Microsoft

Provides the foundational attributes that allow you to declare parts for composition, such as imports, exports, and metadata with the Managed Extensibility Framework (MEF).

System.Composition.Convention by: Microsoft

Provides types that support using Managed Extensibility Framework (MEF) with a convention-based configuration model.

System.Composition.Hosting by: Microsoft

Provides Managed Extensibility Framework (MEF) types that are useful to developers of extensible applications, or hosts.

System.Composition.Runtime by: Microsoft

Contains runtime components of the Managed Extensibility Framework (MEF).

System.Composition.TypedParts by: Microsoft

Provides container configuration and some extension methods for the Managed Extensibility Framework (MEF).

System.Configuration.ConfigurationManager by: Microsoft

Provides types that support using XML configuration files (app.config). This package exists only to support migrating existing .NET Framework code that already uses System.Configuration. When writing new code, use another configuration system instead, such as Microsoft.Extensions.Configuration.

System.Console by: Microsoft

Provides the System.Console class, which represents the standard input, output and error streams for console applications. Commonly Used Types: System.Console System.ConsoleColor