Dear Esoxbum,
If you want something other than the suggested bead head wooly bugger, which is a wonderful fly to dead drift, the simplest thing to do is buy a pack of rubber crayfish and some bare long shank # 4 or 6 hooks. Most of the popular crayfish patterns are far too complicated to tie or expensive to buy. A rubber crayfish and hook with a split shot on the leader will out fish them anyway. If you are using a 7 or 8 weight rod you can even fish them using a 1/16 ounce jig head.
Regards,
Tim Murphy 🙂