A couple free & open-source Engines and game frameworks you can use today as alternatives. Feel free to comment with more.
Godot - https://godotengine.org
MonoGame - https://www.monogame.net/
FNA - https://fna-xna.github.io/
SDL - https://www.libsdl.org/
SFML - https://www.sfml-dev.org/
Adventure Studio - https://www.adventuregamestudio.co.uk/
bgfx - https://github.com/bkaradzic/bgfx
armory3d - https://armory3d.org/
ogre3d - https://www.ogre3d.org/
Renpy - https://www.renpy.org/
#gamedev
Godot - https://godotengine.org
MonoGame - https://www.monogame.net/
FNA - https://fna-xna.github.io/
SDL - https://www.libsdl.org/
SFML - https://www.sfml-dev.org/
Adventure Studio - https://www.adventuregamestudio.co.uk/
bgfx - https://github.com/bkaradzic/bgfx
armory3d - https://armory3d.org/
ogre3d - https://www.ogre3d.org/
Renpy - https://www.renpy.org/
#gamedev
Armory | 3D Game Engine
A powerful, cross-platform, free & open source game engine, integrated in Blender.armory3d.org
This entry was edited (8 months ago)
mcc
in reply to David Amador • • •https://playcanvas.com/
Unity/Godot but it's pure HTML5. Games run in browser, editor runs in a browser. Open source. I think the range of applications where you'd specifically prefer to use it over Godot might be narrow but if you're in that range, I bet it's great.
PlayCanvas - The Web-First Game Engine
PlayCanvas.com