SteamRE

SteamKit

SteamKit2 is a .NET library designed to interoperate with Valve's Steam network. It aims to provide a simple, yet extensible, interface to perform various actions on the network.

DepotDownloader

Steam depot downloader utilizing the SteamKit2 library.

open-steamworks

Open Steamworks is a set of reverse engineered headers for the Valve's Steam Client. More or less abandoned now that the Steamworks SDK is publically available.

Steam4NET

Steam4NET is a .NET wrapper around the Steamworks C++ interfaces

opensteamworks.org