Godot (Game engine)

Godot is an advanced, feature-packed, multi-platform 2D and 3D open source game engine.

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.