Mine grew out of fetching, too.
Personally I don't rotate toys... I don't even know what they've done with half of their toys!
Have your cats had crinkle balls yet? I have one who loves his, I'll have to pick another package up since he's flattening out the one he has. He'll play with it and eventually bat it under something so we have to fetch it out for him... it's aways soggy with cat spit by then.
What I do is pick up some package toys and put the extras in a storage container. I keep a few toys in a plastic baggy with catnip.
Favorites are furry balls, these little fabric balls with feathers on one end (from Walmart), a couple from Kmart called "great balls of fun" (
) - they're fur balls with octopus like legs on them, random balls, and milk jug rings. Oh and one of those large real fur mice that's had most of it's fur licked off of it... We call it "ugly mouse", for some reason they love the horrible looking thing.
Try random toys. If it's a multi pack and a complete strike out maybe you can give the extras to a friend who has cats or donate them to a cat rescue. As always, choose safe toys!