GitHub for Unity's repositories
dotnet-httpclient35
A complete port of Mono's System.Net.Http assembly to .NET 3.5
dugite-native
A toolchain for building a portable, cross-platform Git for applications
octokit.net
A GitHub API client library for .NET
AsyncBridge
Adds the new C# 5 async for older .NET 3.5 and .NET 4.0 projects.
dotnet-threading
Utility library for writing asynchronous code targeting .NET 3.5 and newer