here is one i made from european buckthorn, yes that buckthorn, that aweful noxious stuff, but it is a beatuiful wood, might as well utilize it.
Daisy (as in bb guns) sells slingshot bands, in order of weakest to strongest they are: red, cream, yellow, blue, black. I haven't seen black ones for sale but have seen a slingshot with them, I could hardly pull it back. for hunting, the yellow bands are the way to go i think.
A friend of mine is a slingshot guru, he even pours his own lead shot for ammo and hunts rabbits with them (successfully) all the time. we put a lead ball through a chrono with a "blue banded" slingshot and it registered a bit under 200 fps.