As far as I know, two texture packs currently support attack of the B-Team...
Sphax PureBDCraft (Mod-supported in 32x, 64x, or 128x; also available 16x, 256x, and 512x):
Then, add this to the original pack, above:
Soartex Fanver (Available in 64x only):
Just put this one in your reasource packs folder after download and you're good to go.
I, personally use Soartex Fanver for Attack of the B-Team. It seems to have less of an impact on my framerate (vanilla and modded) and I prefer its look over Sphax. I'll see if I can find more.