itch.io

Games that try to simulate real-world activities (like driving vehicles or living the life of someone else) with as much realism as possible. Simulators generally require more study and orientation than arcade games, and the best simulators are also educational.

Uses two-dimensional "sprites", 2D images created and used on a flat plane, as opposed to the three-dimensional models or environments found in 3D games.

Godot Engine - The free and open source 2D and 3D game engine

Pretty sure everything is indie on itch.io but just in case you want something extra indie.