BYOND - BYOND is the premier community for making and playing online multiplayer games.
ENIGMA – LateralGM - LateralGM is a powerful IDE for ENIGMA, and both of these combine to offer you a cross-platform game environment.
Defold Engine - Defold lets you quickly build high performing, cross-platform games together with your team.
Godot Engine - Feature-packed 2D and 3D open source game engine.
ct.js - ct.js is a 2D game editor (desktop app) based on web technologies.
Lobster - Lobster is a game programming language.