I use my felted sweater scraps for slippers - I cut a leather sole piece for each slipper, minus the seam allowances, and sew that to the wool sole piece before I sew the slippers together. You don't ever want wool-bottomed slippers if you have hard floors in your house!
Other things I use scraps for:
Doll Clothes (jackets, jammies)
or I cut it all up into strips and use the strips to stuff doll bodies and pillows and balls. I've also rolled the strips into balls to use as a base for felted yarn balls. Instead of yarn, though, you could always tack a layer of roving over the outside with a felting needle, and then tie it into a stocking & wet-felt it in the machine. Super easy, and you're using up scraps at the same time. This would be a good way to make some really BIG wool felt balls, without having to pay much of anything for supplies.