Why there are no ads here
I'm an ex-teacher, and I made these games for my own children.
Adverts are built to grab a child's attention and pull them away from what they're doing. I believe having our attention pulled in so many directions as children is damaging.
So there are none. No adverts, no accounts, no tracking, and the games don't ask for money. If you'd like to leave a tip, there's the support page, and never inside a game.