UFC Rules 1-18 define illegal moves--that we train all the time...and their counters.
UFC Fouls ban the following actions:
1. Butting with the head.
2. Eye gouging of any kind.
4. Hair pulling.
5. Fish hooking.
6. Groin attacks of any kind.
7. Putting a finger into any orifice or into any cut or
laceration on an opponent.
8. Small joint manipulation.
9. Striking to the spine or the back of the head.
10. Striking downward using the point of the elbow.
11. Throat strikes of any kind, including, without limitation,
grabbing the trachea.
12. Clawing, pinching or twisting the flesh.
13. Grabbing the clavicle.
14. Kicking the head of a grounded opponent.
15. Kneeing the head of a grounded opponent.
16. Stomping a grounded opponent.
17. Kicking to the kidney with the heel.
18. Spiking an opponent to the canvas on his head or neck.
Engaging in any unsportsmanlike conduct that causes injury to an opponent
Also read: The Myth of Grappling