There's a lot of different corals you can have in a Biocube with stock lighting:
Mushrooms (including Ricordea)
Zooanthids
Yellow Polyps
Frogspawn coral
Hammer coral
Fox coral
Candy cane coral
Blastomussa (blastos)
Torch coral
Plate coral
Check out the nano tank message board and see what other people keep in theirs with stock lighting. Keep in mind that the people on there with anemones and clams do not (or should not, anyway) have stock lighting--they have likely upgraded lighting systems.
Good luck with your new biocube and be sure to post pics along the way to keep us updated on your progress! :cheer: