My cat Phoebe once had a pet BeanieBaby. She eventually lost interest, but she must have carried that thing around for two years.
Phoebe also has a paper fetish, especially toilet paper. If she catches me tearing off a length, I have to let her kill it a few times. She shreds newspaper, too. Fortunately, printer paper isn't the right texture for her.
This was just a one-off, but a couple of weeks ago I was doing a sudoku and my other cat, Sophie, suddenly decided she needed to kill my pencil. It was really strange because Sophie usually isn't playful at all.
My third cat, Carrie, will play with just about anything. Sometimes I find her in the kitchen, chasing a nugget of cat food around the room.
A cat I had years ago kept a pecan hidden somewhere in the living room. He played with it in the middle of the night. (An interesting noise to wake up to)
Generally, though, none of my cats have ever had much interest in bought toys. Not the three I have now; not any I've ever had in the past. They've always prefered found objects: golf balls, plastic bottle caps, scraps of paper, anything dangly or string-like. It's not unusual to wake up in the morning and find some odd small object in the middle of the floor. When my daughter was younger, her toys were always a fertile source for the cats.
Oh, yeah, cardboard boxes. Any size from shoeboxes on up. Those are very important in my household. It's always amusing when cat A is sleeping inside of a box and cat B decides to sit on top of the same box, which holds the flaps closed. Then cat A wakes up, ready to do something else now, thankyouverymuch.