1. That sweep I don't know the name of. Imagine you're in half-butterfly. You lift your hook up slightly. This lets you grab his hooked ankle with your hook-side hand. Your other arm digs under his unhooked leg. Pull his hooked leg towards you with your hand while you push it away with your shin. He gets swept backwards. I also do this one from butterfly if he gets into a combat base to avoid the hook sweep. If he gives me trouble, I'll switch to more normal x-guard or a leglock.
2. Butterfly guard hook sweep. Instead of a overhook on one side, I prefer to grab his wrist and push it between our bodies.
3. Armdrag, take the back. This is only at 3 because I don't really think of it as a sweep. It's more of a submission attempt the way I do it, but it frequently ends up with a sweep as the net result. This is my favorite/best move to turn the tables on a bigger/stronger/better top player in my guard.
The main thing is just to keep trying for them. Sweeps are hard, particularly if you're small or your opponent has good base (wrestlers are particularly hard to sweep). Also, they don't work in isolation unless you have your opponent WAAAY outclassed. You attempt a butterfly sweep, it catastrophically fails, you have to be prepared to immediately switch to something else. X-guard, leglock, whatever. Practice dealing with the things your opponents commonly do to counter your sweeps. I guarantee that they are giving up SOMETHING with every counter they do.
