What are the rules of STABmons?

Question

Is weather legal? What Pokemon are banned? Item legality?

Answer 1

There are no bans other than Sketch outside of Smeargle and standard OU stuff. Although tournaments usually have more bans (OP stuff like SmashPassing).

Source: http://www.smogon.com/forums/threads/stabmons-other-metagame-of-the-month.3484106/