Godot Engine 4

The Godot Engine is a free, all-in-one, cross-platform game engine that makes it easy for you to create 2D, 3D and XR apps and games.

Godot provides a huge set of common tools, so you can just focus on making your game without reinventing the wheel.

Godot is completely free and open-source under the very permissive MIT license. No strings attached, no royalties, nothing. Your game is yours, down to the last line of engine code.