If you are referring to MMA bouts, soft tissue (eyes, ears, throat) small joint manipulation, no kicking a downed opponent are the main ones. I know there are probably others but these are the main ones.
Like Ronin said, if you can't jab someone in the face with your entire fist, what makes you think you can jab them in the eye with a serpent fang or spearhand? Most of these are better suited in the clinch or grappling, but ask yourself this. A good wrestler takes you down and has you mounted or you are in guard, who has control? Do you think you reaching up and clawing like some 6 year old school girl or trying to poke him in the eye is going to get him off? If anything it will p**iss him off more!
Those who are in a position of control are the ones who can probe soft tissue, or manipulate small joints, or reign knees into their head until you turn it into meat pudding. Before you start training to poke eyes, or use small joint manipulation, or whatever else, first learn to control your opponent. Shuai and wrestling practice will allow you to control your opponent, and you have to have control before any of those techniques will work.
"The hero and the coward both feel the same thing, but the hero projects his fear onto his opponent while the coward runs. 'Fear'. It's the same thing, but it's what you do with it that matters". -Cus D'Amato