http library used by C#

RestSharp

RestSharp is a lightweight Http component that does not depend on any third-party components or class libraries.

https://github.com/restsharp/RestSharp

minihttpd

minihttpd: HTTP Web server library

https://www.codeproject.com/articles/11342/minihttpd-an-http-web-server-library

Embedded .NET HTTP Server

Embedded .NET HTTP server

https://www.codeproject.com/Articles/25050/Embedded-NET-HTTP-Server

HttpLib

HttpLib is a free .net (Apache 2.0 license agreement) web request help that makes it easier for developers to access and download resources from the Internet

http://httplib.codeplex.com/

https://github.com/j6mes/httplib/

DotNettySocket

DotNettySocket

Simple and practical Socket framework DotNettySocket

html parsing

HtmlAgilityPack

https://github.com/zzzprojects/html-agility-pack

Provides standard DOM API and XPath navigation for web pages

htmlparser

The difference and choice between WebClient, HttpClient, HttpWebRequest, RestSharp