Balls that have a bell or something rattly inside, annoying noises are always more fun.
Regular balls too.
Mousies, as others have said, some are better than others, no telling what they'll prefer till you give them it!
Feathers from the shop.
Plastic shoppijng bags, actually any bag, even better if it still has shopping in it.
Boxes, again if it has some packaging in it then so much the better.
A large cat tree, flying at it from all agngles is most fun.
Lastly, Dave like to tip over the bin in the bathroom to find his favourite thing ever, cotton buds. I try to remember not to put them in that bin because I don't like him playing with them but they just mysteriously appear sometimes and he will play with it for hours given half the chance
