Wallpapers
A collection of big patterns that you can put in your playpen! You could probably use them as textures for hexing if you really want to, though.
The files in here go right in your Wallpapers folder in the Petz folder.
Sims 3 Create-a-Pattern Patterns
I know this is like crazy niche but I was looking through The Sims 3 Create a Pattern program and saw some neat repeating patterns I could use. This .zip contains 14 wallpapers, some a little easier on the eyes than others so I don't mind if you pick and choose which ones you want to use.