A very popular instructor on here favors Fred Kelly Delrin picks. Order them large though.

Another popular one are Alaska Picks or the usual Dunlops you'll find in the stores. The first two you'll have to order.

Alaska picks actually go under the fingernail so you'll need at least a little growth there. I personally could not get used to any of them so I just use my fingers. If your just starting then it might be good to get the feel of them right from the getgo. It's harder to do later on.