Xenia is easy to grow, unless it decides it doesn't like the current or surrounding corals. Mine grows like wildfire in the algae scrubber, but dies in the main display tank. Kenya tree is easy to grow and if you surround it with mushrooms like I have, it stays in check. I like octocorals like anthellia and LPS
corals like frogspawn. Green star polyps and most zoas are easy as well.