All known patterns here

Banners will be a thing in 1.8. I don't know about you, but I think this is HUGE. It finally adds a way to create markers or symbols that could be added everywhere without relying on signs or huge pixel artwork. Up to six symbols/patterns can be stacked on a single pattern using the 16 dye types, so the number of possibilities is large (400^6).

I can easily imagine cities (or even players) coming up with their own patterns. Heck, they could even be used to visually identify railways!