Blenny's & fireworms, I make a #1 with my first finger and wiggle it. if I'm over a round coral head and point to a hole...it's a blenny. If I'm just over the reef, it's most likely a fireworm.
I do Mossman's thing for nudies, then make the "worm" sign..."tiny worm"
I also do MOST of my hand signals with one hand, if possible, because of carrying a camera. Like for turtle I basically make a 'shaka' and wiggle my thumb and pinky in a circular motion, rather than putting one hand on top of the other and wiggling the thumbs.
In case you want to id individual turtles; hawksbill: make your fist look like a hawksbill with your fingers protruding over your thumb. Green: make a fist and bend your wrist a little, it looks like a geen's head, more rounded than a hawksbill. Loggerhead: bump your fist on your forehead and make the turtle sign.
Trumpets are easy, play the trumpet
grouper, rub your tummy (they're good to eat)