Those are metallic mushrooms, I think, a discosoma species, and two kinds of polyps or zoas, the small 'brown', which glow green in actinic, if I'm right, and the larger brown. They're pleasant tank cover, and I always liked them when I kept softies.
Sidenote: You also have the start of an alga you might like to get rid of asap: that stuff can get nasty. Consider an algae eater appropriate to your tank size, and skim hard. The coralline will partially protect you from it, but it's bad when it gets a foothold: you may have too much phosphate, and it won't show on tests, if it's 'bound' in algae.