Top 5 vmf open source projects

Tools for map compiling in Source Engine, tailored for Garry's Mod (and metastruct, sorry)

An open-source, community-run framework that provides enhanced Vermintide modding support.

A Valve Map Format (.vmf) and Valve Material Type (.vmt) importer for Blender.

C# parsers and formats for Half-Life 1 and related engines.

A custom Source Engine level editor written in Go