BYOND - BYOND is the premier community for making and playing online multiplayer games.
Blitz3D - Create 2D and 3D Games for Windows.
Defold Engine - Defold lets you quickly build high performing, cross-platform games together with your team.
BlitzPlus - Create 2D Games for Windows.
ct.js - ct.js is a 2D game editor (desktop app) based on web technologies.
Monkey 2 - An easy to use, cross platform, games oriented programming language