Gobies and blennies are my first recommendations for new (freshly cycled) tanks followed by clowns, with damsels being controversial because of their attitude. Some of the bottom dwelling gobies like the popular watchman and diamond back might be small, but they are very, very hardy and good beginner fish. Tangs, angels and butterflys should be avoided until the tank becomes more mature.
Snails, hermit crabs, and sally lightfoot crabs are good additions for starters. Assuming of course you have algae growing on the rocks.
Shrimp are another matter. Cleaner shrimp and fire shrimp (similiar species) are a bit sensitive to new tanks, especially PH
fluctuations. Coral banded shrimp are more hardy in regards to new tank syndrome, but more aggresive towards other shrimp. I've had my resident coral banded survive 3 tanks moves and a few ignorance induced ammonia spikes with no problems. He's getting bold enough and big enough to take chunks of meat from my hand as well.
Most mushrooms, especially the popular blue/green will do fine in your tank and will spread like crazy given a good food source. Place them up towards your lights.