They have lots of toys but their favorite thing is an old black string
Also any string with feathers does the trick
if you're too busy there are laser pointers that go in circles and point on their own.
The one posted in the pic loos good too.
As mentioned above boxes with holes, paper bags big enough for them to go in.
Mousey toys. I noticed they like the ones that are more flat. Maybe it resembles more real mice.