It's not limited to Rpg maker, I'm writing this because it's adapted to Rpg maker right out of the box, but every engine that uses 32X32,48x48 or more pixels in the cube.Format is PNG. But with a little work, a person can adapt it to every engine if they understand it a little.Then there are animations that are 3x sprites in a table for each animation, as you can see on the last screen. I have some packs for free download(just for free projects, commercial do donation(£1-2), test them if you know how and adapt them to Godot, just for testing, I have no problem with all the packs that are bought being used for other engines than commercial in project. As long as you don't sell them separately.