If you buy a trigger for a reef tank, ONLY buy a trigger if it is PROVEN reef safe, eg - its come from a customer or display tank with corals! There is no such thing as a reef safe trigger, its more of a case of reef safe individuals! Some species are less prone to be reef munchers like the pink tails but within that, it depends on personality, i had one and it destroyed EVERYTHING in the tank.
You dont say what sort of corals you have, softies, lps or sps corals etc, there are species that are worse with one or the other...
I had a HUGE copperband Butterfly who was a star, didnt even look at the corals, let alone pick at them! Some other stunning Butterflies too, the 'racoon butterfly', i've never seen one pick at corals but like i said, nothing is completely reefsafe when confined to an aquarium... and the Collare Butterfly, stunning stunning fish! Can be a bit iffy...
Yellow Tangs, Purple Tangs and Scopas Tangs are all great, especially one of each, love em! Ooh and look up Clown Tang, they are brilliant! And Powder Brown/Gold Rim Tang. Personally, i wouldnt touch a Powder Blue with a barge pole with out a HUGE tank and a very good UV Steraliser and very mature tank and even then, huge risk, they are so so SO prone to whitespot and once they get it... panic because it isnt easy to get fish out once they are in and even harder to treat tanks when it spreads! Only geto ne if you like a risk! Powder Browns/Gold Rims seem to be a lot hardier.
Radiata or Fuzzy Dwarf Lionfish make great centerpieces in the right tank, just not with small fish or shrimps! I love volitans (and have one) but they do get HUGE.
Sailfin Tangs are beautiful and as are Sohal tangs too...