Anything that moves once it's been touched - they see it moving and instantly pounce on it which makes it move more etc.
Sparkly tinsel balls, springs, mini foam footballs etc all get played with several times a day.
They also like kicker toys (stuff they grab with their front paws and kick with the back legs). I have a few, some with cat nip in, some without.
For active play I have laser pens (ones safe for eyes), a feather on an extra long pole and string toy that gets some very impressive leaps out of them, and a duck on elastic that hangs in a doorway.
They are 13 now and still play with the above. I've tried lots of more expensive techy toys over the years but these are what they consistently liked.
I keep a big box in a cupboard and when they stop using something for a week or so it goes in the box and something else comes out, so there is a constant novelty in what is available.