System.Data.SqlClient by: Microsoft

Provides the data provider for SQL Server. These classes provide access to versions of SQL Server and encapsulate database-specific protocols, including tabular data stream (TDS) Commonly Used Types: System.Data.SqlClient.SqlConnection System.Data.SqlClient.SqlException System.Data.SqlClient.SqlParameter System.Data.SqlDbType System.Data.SqlClient.SqlDataReader System.Data.SqlClient.SqlCommand System.Data.SqlClient.SqlTransaction System.Data.SqlClient.SqlParameterCollection System.Data.SqlClient.SqlClientFactory

System.Diagnostics.DiagnosticSource by: Microsoft

Provides Classes that allow you to decouple code logging rich (unserializable) diagnostics/telemetry (e.g. framework) from code that consumes it (e.g. tools) Commonly Used Types: System.Diagnostics.DiagnosticListener System.Diagnostics.DiagnosticSource

System.Diagnostics.Tools by: Microsoft

Provides attributes, such as GeneratedCodeAttribute and SuppresMessageAttribute, that are emitted or consumed by analysis tools. Commonly Used Types: System.CodeDom.Compiler.GeneratedCodeAttribute System.Diagnostics.CodeAnalysis.SuppressMessageAttribute

System.Diagnostics.TraceSource by: Microsoft

Provides classes that help you trace the execution of your code. Developers should prefer the classes in the ETW-based System.Diagnostics.Tracing package.

System.IO.Compression by: Microsoft

Provides classes that support the compression and decompression of streams. Commonly Used Types: System.IO.Compression.DeflateStream System.IO.Compression.GZipStream System.IO.Compression.CompressionMode System.IO.Compression.CompressionLevel System.IO.Compression.ZipArchiveEntry System.IO.Compression.ZipArchive System.IO.Compression.ZipArchiveMode

System.IO.Compression.ZipFile by: Microsoft

Provides classes that support the compression and decompression of streams using file system paths. Commonly Used Types: System.IO.Compression.ZipFile

System.IO.FileSystem.Watcher by: Microsoft

Provides the System.IO.FileSystemWather class, which listens to the file system change notifications and raises events when a directory, or a file in a directory, changes. Commonly Used Types: System.IO.FileSystemWatcher System.IO.WatcherChangeTypes System.IO.FileSystemEventArgs System.IO.RenamedEventArgs System.IO.FileSystemEventHandler System.IO.RenamedEventHandler System.IO.NotifyFilters System.IO.ErrorEventArgs System.IO.ErrorEventHandler System.IO.WaitForChangedResult

System.Linq.Async by: .NET Foundation and Contributors

Provides support for Language-Integrated Query (LINQ) over IAsyncEnumerable<T> sequences.

System.Linq.Queryable by: Microsoft

Provides classes for querying data structures that implement IQueryable<T>. Commonly Used Types: System.Linq.Queryable System.Linq.EnumerableQuery<T> System.Linq.EnumerableQuery

System.Net.Http by: Microsoft

Provides modern classes for sending HTTP requests and receiving HTTP responses from a resource identified by a URI. Commonly Used Types: System.Net.Http.HttpResponseMessage System.Net.Http.DelegatingHandler System.Net.Http.HttpRequestException System.Net.Http.HttpClient System.Net.Http.MultipartContent System.Net.Http.Headers.HttpContentHeaders System.Net.Http.HttpClientHandler System.Net.Http.StreamContent System.Net.Http.FormUrlEncodedContent System.Net.Http.HttpMessageHandler

System.ObjectModel by: Microsoft

Provides types and interfaces that allow the creation of observable types that provide notifications to clients when changes are made to it. Commonly Used Types: System.ComponentModel.INotifyPropertyChanged System.Collections.ObjectModel.ObservableCollection<T> System.ComponentModel.PropertyChangedEventHandler System.Windows.Input.ICommand System.Collections.Specialized.INotifyCollectionChanged System.Collections.Specialized.NotifyCollectionChangedEventArgs System.Collections.Specialized.NotifyCollectionChangedEventHandler System.Collections.ObjectModel.KeyedCollection<TKey, TItem> System.ComponentModel.PropertyChangedEventArgs System.Collections.ObjectModel.ReadOnlyDictionary<TKey, TValue>

System.Reflection.Emit.ILGeneration by: Microsoft

Provides clases that allow a compiler or tool to emit Microsoft intermediate language (MSIL). The primary clients of these classes are script engines and compilers. Commonly Used Types: System.Reflection.Emit.ILGenerator System.Reflection.Emit.Label System.Reflection.Emit.CustomAttributeBuilder System.Reflection.Emit.LocalBuilder System.Reflection.Emit.ParameterBuilder System.Reflection.Emit.SignatureHelper

System.Runtime.Extensions by: Microsoft

Provides commonly-used classes for performing mathematical functions, conversions, string comparisons and querying environment information. Commonly Used Types: System.Math System.Environment System.Random System.Progress<T> System.Convert System.Diagnostics.Stopwatch System.Runtime.Versioning.FrameworkName System.StringComparer System.IO.Path

System.Runtime.Serialization.Primitives by: Microsoft

Provides common types, including System.Runtime.Serialization.DataContractAttribute, for libraries that support data contract serialization. Commonly Used Types: System.Runtime.Serialization.StreamingContext System.Runtime.Serialization.OnDeserializingAttribute System.Runtime.Serialization.OnDeserializedAttribute System.Runtime.Serialization.OnSerializingAttribute System.Runtime.Serialization.OnSerializedAttribute System.Runtime.Serialization.EnumMemberAttribute System.Runtime.Serialization.DataMemberAttribute System.Runtime.Serialization.DataContractAttribute System.Runtime.Serialization.IgnoreDataMemberAttribute System.Runtime.Serialization.SerializationException

System.Security.Cryptography.Encoding by: Microsoft

Provides types for representing Abstract Syntax Notation One (ASN.1)-encoded data. Commonly Used Types: System.Security.Cryptography.AsnEncodedData System.Security.Cryptography.Oid System.Security.Cryptography.OidCollection

System.Text.Encoding.CodePages by: Microsoft

Provides support for code-page based encodings, including Windows-1252, Shift-JIS, and GB2312. Commonly Used Types: System.Text.CodePagesEncodingProvider

System.Text.Json by: Microsoft

Provides high-performance and low-allocating types that serialize objects to JavaScript Object Notation (JSON) text and deserialize JSON text to objects, with UTF-8 support built-in. Also provides types to read and write JSON text encoded as UTF-8, and to create an in-memory document object model (DOM), that is read-only, for random access of the JSON elements within a structured view of the data. Commonly Used Types: System.Text.Json.JsonSerializer System.Text.Json.JsonDocument System.Text.Json.JsonElement System.Text.Json.Utf8JsonWriter System.Text.Json.Utf8JsonReader System.Text.Json.Nodes.JsonNode System.Text.Json.Nodes.JsonArray System.Text.Json.Nodes.JsonObject System.Text.Json.Nodes.JsonValue

System.Threading by: Microsoft

Provides the fundamental synchronization primitives, including System.Threading.Monitor and System.Threading.Mutex, that are required when writing asynchronous code.

System.Threading.Thread by: Microsoft

Provides the System.Threading.Thread class, which allows developers to create and control a thread, set its priority, and get its state.

System.Threading.Timer by: Microsoft

Provides the System.Threading.Timer class, which is a mechanism for executing a method at specified intervals. Commonly Used Types: System.Threading.Timer System.Threading.TimerCallback