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. The System.Text.Json 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.Text.RegularExpressions by: Microsoft

Provides the System.Text.RegularExpressions.Regex class, an implementation of a regular expression engine. Commonly Used Types: System.Text.RegularExpressions.Regex System.Text.RegularExpressions.RegexOptions System.Text.RegularExpressions.Match System.Text.RegularExpressions.Group System.Text.RegularExpressions.Capture System.Text.RegularExpressions.MatchEvaluator When using NuGet 3.x this package requires at least version 3.4.

System.Threading by: Microsoft

Provides the fundamental synchronization primitives, including System.Threading.Monitor and System.Threading.Mutex, that are required when writing asynchronous code. Commonly Used Types: System.Threading.Monitor System.Threading.SynchronizationContext System.Threading.ManualResetEvent System.Threading.AutoResetEvent System.Threading.ThreadLocal<T> System.Threading.EventWaitHandle System.Threading.SemaphoreSlim System.Threading.Mutex When using NuGet 3.x this package requires at least version 3.4.

System.Threading.AccessControl by: Microsoft

Provides support for managing access and audit control lists for synchronization primitives. Commonly Used Types: System.Security.AccessControl.EventWaitHandleAccessRule System.Security.AccessControl.EventWaitHandleAuditRule System.Security.AccessControl.MutexAccessRule System.Security.AccessControl.MutexAuditRule System.Security.AccessControl.MutexSecurity System.Security.AccessControl.SemaphoreAccessRule System.Security.AccessControl.SemaphoreAuditRule System.Security.AccessControl.SemaphoreSecurity

System.Threading.Channels by: Microsoft

Provides types for passing data between producers and consumers. Commonly Used Types: System.Threading.Channel System.Threading.Channel<T>

System.Threading.RateLimiting by: Microsoft

APIs to help manage rate limiting. Commonly Used Types: System.Threading.RateLimiting.RateLimiter System.Threading.RateLimiting.ConcurrencyLimiter System.Threading.RateLimiting.TokenBucketRateLimiter System.Threading.RateLimiting.RateLimitLease

System.Threading.Tasks.Dataflow by: Microsoft

TPL Dataflow promotes actor/agent-oriented designs through primitives for in-process message passing, dataflow, and pipelining. TDF builds upon the APIs and scheduling infrastructure provided by the Task Parallel Library (TPL), and integrates with the language support for asynchrony provided by C#, Visual Basic, and F#. Commonly Used Types: System.Threading.Tasks.Dataflow.ActionBlock<TInput> System.Threading.Tasks.Dataflow.BatchBlock<T> System.Threading.Tasks.Dataflow.BatchedJoinBlock<T1, T2> System.Threading.Tasks.Dataflow.BatchedJoinBlock<T1, T2, T3> System.Threading.Tasks.Dataflow.BroadcastBlock<T> System.Threading.Tasks.Dataflow.BufferBlock<T> System.Threading.Tasks.Dataflow.DataflowBlock System.Threading.Tasks.Dataflow.JoinBlock<T1, T2> System.Threading.Tasks.Dataflow.JoinBlock<T1, T2, T3> System.Threading.Tasks.Dataflow.TransformBlock<TInput, TOutput> System.Threading.Tasks.Dataflow.TransformManyBlock<TInput, TOutput> System.Threading.Tasks.Dataflow.WriteOnceBlock<T>

System.Threading.Tasks.Extensions by: Microsoft

System.Threading.Tasks.Extensions

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. Commonly Used Types: System.Threading.Thread System.Threading.ThreadStart System.Threading.ParameterizedThreadStart When using NuGet 3.x this package requires at least version 3.4.

System.Threading.ThreadPool by: Microsoft

Provides the System.Threading.ThreadPool class, which contains a pool of threads that can be used to execute tasks, post work items, wait on behalf of other threads, and process timers. Commonly Used Types: System.Threading.ThreadPool System.Threading.WaitOrTimerCallback When using NuGet 3.x this package requires at least version 3.4.

System.ValueTuple by: Microsoft

System.ValueTuple

System.Web.Services.Description by: Microsoft

Contains classes that enable you to publicly describe an XML Web service by using the Web Services Description Language (WSDL).

System.Windows.Extensions by: Microsoft

Provides miscellaneous Windows-specific types Commonly Used Types: System.Security.Cryptography.X509Certificates.X509Certificate2UI System.Security.Cryptography.X509Certificates.X509SelectionFlag

System.Xml.ReaderWriter by: Microsoft

Provides provides a fast, non-cached, forward-only way to read and write Extensible Markup Language (XML) data. Commonly Used Types: System.Xml.XmlNodeType System.Xml.XmlException System.Xml.XmlReader System.Xml.XmlWriter System.Xml.IXmlLineInfo System.Xml.XmlNameTable System.Xml.IXmlNamespaceResolver System.Xml.XmlNamespaceManager System.Xml.XmlQualifiedName When using NuGet 3.x this package requires at least version 3.4.

System.Xml.XDocument by: Microsoft

Provides the classes for Language-Integrated Query (LINQ) to Extensible Markup Language (XML). LINQ to XML is an in-memory XML programming interface that enables you to modify XML documents efficiently and easily. Commonly Used Types: System.Xml.Linq.XElement System.Xml.Linq.XAttribute System.Xml.Linq.XDocument System.Xml.Linq.XText System.Xml.Linq.XNode System.Xml.Linq.XContainer System.Xml.Linq.XComment System.Xml.Linq.XObject System.Xml.Linq.XProcessingInstruction System.Xml.Linq.XDocumentType When using NuGet 3.x this package requires at least version 3.4.

System.Xml.XmlDocument by: Microsoft

Provides an older in-memory Extensible Markup Language (XML) programming interface that enables you to modify XML documents. Developers should prefer the classes in the System.Xml.XDocument package. Commonly Used Types: System.Xml.XmlNode System.Xml.XmlElement System.Xml.XmlAttribute System.Xml.XmlDocument System.Xml.XmlDeclaration System.Xml.XmlText System.Xml.XmlComment System.Xml.XmlNodeList System.Xml.XmlWhitespace System.Xml.XmlCDataSection When using NuGet 3.x this package requires at least version 3.4.

System.Xml.XmlSerializer by: Microsoft

Provides classes for serializing objects to the Extensible Markup Language (XML) and deserializing XML data to objects. Commonly Used Types: System.Xml.Serialization.IXmlSerializable System.Xml.Serialization.XmlSerializer System.Xml.Serialization.XmlIgnoreAttribute System.Xml.Serialization.XmlElementAttribute System.Xml.Serialization.XmlAttributeAttribute System.Xml.Serialization.XmlArrayAttribute System.Xml.Serialization.XmlRootAttribute System.Xml.Serialization.XmlArrayItemAttribute System.Xml.Serialization.XmlTypeAttribute System.Xml.Serialization.XmlEnumAttribute When using NuGet 3.x this package requires at least version 3.4.

TimeZoneConverter by: Matt Johnson-Pint

Lightweight library to convert quickly between IANA, Windows, and Rails time zone names.

TinyIoC by: Steven Robbins

An easy to use, hassle free, Inversion of Control Container for small projects, libraries and beginners alike

Topshelf by: Chris Patterson, Dru Sellers, Travis Smith

Topshelf is an open source project for hosting services without friction. By referencing Topshelf, your console application *becomes* a service installer with a comprehensive set of command-line options for installing, configuring, and running your application as a service.