Zorro will play with a radish for hours... flicking it, chasing it...! It's especially good if he can steal one whilst I'm preparing them.
Cork drink coasters used as frisbees are good too. And chunks can be bitten out of them and used to decorate the floor...
Pliable wire [current favourite is that chopped from a defunct mobile phone charger] which is tied up into a knot that needs unravelling... This one is mainly used to distract him from chewing my computer wiring.
Meanwhile, the expensive Da Bird imported from UK gets totally ignored!
Do your cats have unusual non-purchased toys?