GitHub - Originally founded as a project to simplify sharing code, GitHub has grown into an application used by over a million people to store over two million code repositories, making GitHub the largest code host in the world.
Godot Engine - Feature-packed 2D and 3D open source game engine.
GitLab - Create, review and deploy code together with GitLab open source git repo management software | GitLab
Unreal Engine - Unreal Engine 4 is a suite of integrated tools for game developers to design and build games, simulations, and visualizations.
BitBucket - Bitbucket is a free code hosting site for Mercurial and Git. Manage your development with a hosted wiki, issue tracker and source code.
BYOND - BYOND is the premier community for making and playing online multiplayer games.