Endless Sky

Clone of the Age of Empires II engine

Open-source engine for Heroes of Might and Magic III

C++20 framework for creative coding / Cross-platform support (Windows, macOS, Linux, and the Web)

Naev has moved to codeberg! This is just a mirror.

Open-source, cross-platform 2D/3D/multiplayer game engine designed for everyone.

Scalable open-source game backend server: multiplayer, matchmaking, leaderboards, chat, and social features for games.