If you search any of the online music stores for "arranged for easy piano" you'll get heaps of what you're after.
Many years ago when I was teaching myself to play, I made use of www.ichigos.com's fan arrangements of different video game/anime music. Some sheets there are advanced, but most are very simple! Another thing I suggest would be to visit a music store that sells piano scores (perhaps even with a piano you can sit down at in-store to give the music a quick test run) and see if they have any easy to play anime/video game music that may appeal to you. If this is an option, I'd definitely try it out! Best wishes!