rather than concentrating on "wrist grabs", focus your study on "attachment and kuzushi", so that anywhere you're grabbed you are able to disorient your attacker and break their structure. Nobody likes to fight "off balance", and if you use whatever attachment you have with the attacker, from blocking a punch to being grabbed, you use it to disable your opponent and lead them wherever you want them to go.
Like I said, there are a million different ways to use that mechanical attachment, whether at the wrist, elbow, shoulder, etc. to off-balance and redirect your attacker's energy. Using that, and simple body mechanics, you should be able to handle most situations without effort.
"All techniques work sometimes... good techniques work whenever you use them"... and that's because you use the mechanical attachment, personal structure of your opponent, and his energy against him. We could write books about "wrist techniques", and still not cover them all, but it doesn't take much training to learn how to use "attachment" and "kuzushi" to keep someone off balance long enough to protect yourself.