Here's something cool for tiles and other textures! http://www.spiralgraphics.biz/viewer/ The Genetica Viewer is a program that allows you to see (the thousands) of textures that other users have created. There is also a Genetica Studio where you can make your own, costs money but there is a demo! It's really interesting. I've tried it out myself and while it's not especially beginner-friendly, it's definitely worth dicking around with.