I've often wondered this as Rini doesn't really play with much.
I have a large rattle ball, rope ball, wooden carrot, rope toy and a cat toy in her cage and she throws the cat toy around the most.
Why not try to get some ideas from this site?

Toys for Your Rabbit

Only thing I'm not sure about on there from a glance is the rattle soda can idea... tho it does tell you to file it down but some people might not do it enough and it might still be sharp for a bunny :/

A toy that was a big hit with Rini was a hay ball from a pet shop, she played with it for abit them ate it lol, there was a big bell inside that I took out as soon as she would have been able to reach it.