Basic rabbit strip flies work well for most any species. They consist of a rabbit strip tail, and a wrapped body of rabbit strip. Most use cross-cut rabbit for the body, but straight cut can be used too. You can add some flash into the tails too if you like, and they can be weighted, either with wrapped wire (lead or non-lead as you like), cone or bead heads, or barbell eyes /bead chain eyes which can cause them to ride inverted like a Clouser Minnow.
Many options for tying them, particularly with all the color options that rabbit strips are available in! Plus, the style of fly works well to imitate many prey species, from baitfishes, to crawfish to leeches.
These are all rather large, but the basics are the same!
A bit more involved with materials, but not difficult to tie!
Another simple streamer I like & have used a lot is this one: Clouser Minnow style leech pattern tied with ostrich herl, and a bit of flashabou (copper, bronze, black, or gold). Tie it full, as it slims down a lot.