Search Google for "GDStyler" (it's often hosted on gdstyler.web.app or similar fan sites).
If you want true custom drawing (not just recoloring existing icons), you need . geometry dash icons maker
This ecosystem means that when you see a player enter a level, their icon is a résumé. A player with a specific glowing sword or a rare "death effect" isn't just stylish; they are experienced. Search Google for "GDStyler" (it's often hosted on gdstyler