My cats love straw woven balls and cages, especially with catnip in them, and chase them all around the house before destroying them. They also like fabric stuffed toys, again with catnip on them. I often buy liver dog treats for the cats (?Biljack?) and although they are a challenge for them to chew up, they work at it and succeed. When I am being easy on them, I just break the liver treats in half for them. I give the cats the femur and tibia of turkey legs after I have removed most of the meat and the other, smaller bone. They can't get their mouth open far enough to crack the poultry bones to splinters, but they can knaw off the ends where it is softer. I will also give them rib bones of pork or beef.
A favorite cotton/fabric type toy they really like is a stuffed ribbon or snake shape which they like to tackle and chew the head off while kicking with their back legs to ceremoniously disembowel it: yikes, toy guts all over the floor!!! How horrible!