This is a set of flat gamepad overlays I did, based on PPSSPP standalone overlay. There are 16 overlays in total, you can find them in overlays/gamepads/flat/ folder
Some of them have different sizes (A & B overlays), others have different types / buttons position, like Genesis and PSP.
You can use it with the overrides files enabled, so it’ll automatically load an overlay for each Core, just go to Settings --> Configuration --> Load Override Files Automatically = ON, download [b]this config[/b] and put it on your folder you configured in Settings --> Directory --> Config Dir
RetroArch has a little problem when load overlays, so choose the retropad-fast.cfg as the default gamepad overlay instead retropad.cfg (which is more complete but slow to load, depending on your device).
Take a look at the gallery: