Heads up, you may want to rethink easy to care for AND fast growing corals. I felt the same way when I was first starting and went through hell trying to remove things like xenia, button polyps, and trumpet mushrooms. Rather than getting coral that will show major growth, you should focus on easy to keep corals that you could see in your ideal tank 5 years from now. Corals such as frogspawn, torches, duncans, and zoanthids are easy to care for but look stunning in a mixed reef and grow at a moderate and controllable pace.