it really depends on what you mean by weak wrists.....
there's no muscle tissue right around your actual wrist joint. Strengthening joints themselves is not really a thing that can be done. You can strengthen your forearms, but that has limited application. I also have very small, generally weak wrists. I've had wrist problems my whole life. wrist wraps have been an extremely useful tool for me. I use them to bench press anything over about 200 lbs, and I use them for all of my overhead pressing. They just add support, so you're less likely to injure them.
But since you asked about specific exercises, I am going to recommend heavy carries and holds to strengthen forearms. Holding a heavy weight for time is immensely useful in building forearm strength. Hangs from a bar can do the same. Farmers carries and frame carries are awesome. I did one arm hangs for awhile, trying to do 20 seconds at a time, and they were incredibly taxing, but effective. I wouldn't expect you to be able to do those, but maybe you could do something comparable with both arms.
One thing I will say about forearm/grip work, is that it should be limited. It's going to make almost every other lift in the gym more difficult, if your grip is constantly fried. I train grip once a week at most. My forearms, while very very strong, were also constantly in pain for awhile because I did so many things (heavy deadlifts, rows and carries), without ever using straps. Just figure out what works for you and how much you can tolerate. Don't be afraid to use straps sometimes.