In a 66ish tank, assuming 18"X18"X36", you will have plenty of option. You should have a tight cover, then flasher and fairy wrasse have some of the most beautiful fish that is suitable for this tank. They jump so cover is a must.
Flame angel pair, or other dwarf angels are good choice for a 65 gal tank. Clown fish and anemone, or Mandarin.
Words of caution: Mandarin only eat live food, tiny crustacean in sand and rock. The tank must be setup to facilitate this or else they won't live. There are many people will state that they can feed Mandarin, and they don't have to have live food. They can but not without huge effort that I don't want to spend. Fishes that are good hunters will out compete Mandarin for food, thus starve them. Dwarf angels, certain wrasse must be avoid in a smallish tank, your tank, with mandarin in it.
Anemone are not the easiest animals to keep alive, especially host anemones for Percula or Ocellaris Clowns. You can keep them with non natural host, like BTA (E. quadricolor) but interaction between clowns and non natural hosts are not anywhere near as good as with natural hosts.
Here are two of my wrasse, Yellow Fin Flasher and Carpenter Flasher
and McCosker Flasher
You may also want to add a Flame angel pair
Male
Female
INSTEAD of Angel, you may want to add a Mandarin Male. You don't have a big enough tank for a pair of mandarin, but if you set your tank up correctly and not have food competitors, you can keep one. Here is my Male
My female
A. percula pair and their anemone is always the fish people see when they look at your tank.
A. percula in my Magnifica