It's true that there are only so many things you can do with your fingers when it comes to hand signs, handshakes, and what not.
The devil is rocking angel wings too. But those aren't bad...it's because he used to be an angel.
Likewise, the devil wants nothing more than to be powerful, kingly, and adored like God. So he will strike all kinds of poses to that end. Remember, the devil "apes" God or tries his utmost to imitate Him. Usually with a twisted, demonic version. God invented marriage, Satan responded with "open marriage", the orgy, shacking up, sodomy, and same sex marriage. The devil has his own prayers too, which his dupes pray to him. God has the Ten Commandments and the Two Great Commandments, the devil responds with "do what thou wilt".
Anyhow, hand signs aren't like the 8-note musical scale, which is capable of millions of different melodies. I'm sure every possible pose of the fingers has been "taken" by some group, organization, or gang.