This is what's large and in my tank that I know of. There's also a lot of millimetre size crustaceans & worms & so on. The small starfishes and snails breed prolifically in the tank, there appear to be 20 to 40 of each at any given time.
Fish	Invertebrates	Plants
rock blackfish ("drummer")	sea urchin; sea anemones; prawns	kelp
stripey	crabs; hermit crabs	various green / brown sea plants
mullet	white Sydney coral with green polyps	green macro algae
assorted small bait fish	sponge with red fanning branches	green algae
damsel sergeant major	orange bubbly sponge or anemone	Neptune's Necklace (tidal -> deceased)
rock cods	15cm 10-leg starfish
skippers / gobys	10cm 5-leg brittle star
smooth toad fish	3cm 5-leg starfishes
'tropical' yellow with blue stripes & spot	giant clam (baby 6cm)
damsel yellow tail	pipis; clams; limpets; oysters
clown fish (exotic from pet shop)	assorted snails; 10cm giant snail
bicolour angel (exotic from pet shop)	barnacles; tiny cone shells