Orzhov is surprisingly good, lots of good curvy commons/uncs. Simic seems like it can be slow (it might be the Golgari of the set). Gruul is just trading blows. Dimir has lots of unblockables.
The format is still removal-light, so Cipher stuff + Dimir unblockables is pretty good, as is stuff like Orzhov's 1(W/(W/ aura that gives +1/+1 lifelink and flying
A RUG Gruul-Simic build went 4-0 winning 8 straight games thanks to a combination of creatures that were tricks, removal, and guys that just kept getting bigger.