I personally love the following: Kuroshitsuji, Katekyo Hitman REBORN!, and D.Gray-Man for the plots. Those also have a lot of fanart so it should be easy to find PNGs or vectors. And if all else fails, do some Final Fantasy, for the art is absolutely amazing. Hm :/ my list of anime grows smaller every time I think about it... I wonder if I'm falling out of love with it.