Standing guillotines, etc. are useful. I don't have much faith in wrist locks (while standing) and stuff like that because it's hard enough to get a grip on someone's hand while fighting (in a mma context), let alone keep that grip and apply a lock while the rest of their body is free to move and resist. If I get a grip on someone's wrist, I would rather use an arm drag or 2-on-1 and then work from the superior position than just stand in front of someone. A lot of wrist locks require you to focus both of your hands on one or theirs while they are still free to move, hit you, etc.