https://godotengine.org/

https://o3de.org/

https://defold.com/

https://www.stride3d.net/

https://gdevelop.io/

https://armory3d.org/

https://torque3d.org/engine/

https://flaxengine.com/

https://pragma-engine.com/

https://wickedengine.net/

https://www.adventuregamestudio.co.uk/

https://castle-engine.io/

https://solarus-games.org/

Here's a quick one as I'm on a movie break. I'll make a note to update this in the morning.

Haxe + Haxeflixel : pixel art games

Haxe + Heaps : More general 2d/3d framework with webgl target

Godot : I havent used it personally but I've had a myriad of co-workers tell me how good it is

Monogame/FNA : Open source multi-target C# framework that more or less fits the XNA api. I love this one. Might be really good for C# programmers.