There absolutely loads of things that you can do with a medicine ball but many require a bit of space. I also think that there are lots more possibilities if you train with a partner. I used to train with a coach (athletics) and used to do about a 1 hour session with medicine balls before the gym and he had me and others doing some great stuff with them and it was pretty fun(ish) too.
A lot of the stuff with a partner involved some kind of throwing. For example, one person seated with back and legs raised while the other throws ball to seated person at each point of the clock around their body and then the seated partner returns the ball as quickly as possible whilst maintaining position.
They are pretty versatile and there are some guides to using them solo about too. If you want to use them for throwing about then don’t go too heavy as they loose the versatility. The way that you use them and the positions you put your body in can increase leverage on muscles so heavy weight isn’t required.