Pretty much all peaceful fish and semi-aggressive get along. Go on liveaquaria.com for quick stats and info. Research the fish you want before getting it! Damsels can be very territorial and aggressive like you said.
Gobies would work fine, but a yellow tang sadly wouldn't. They grow too large to be in anything less than bare minimum 90 or 125. Many hobbyists say that a 6 foot tank is the minimum for any tang except for the tomini and bristletooth tang. There are lots of fish besides tangs though!
A firefish would work well. They are very docile so it would be best to add that next if you were getting one. Goby and possibly some type of blenny would be cool too. IMO
you shouldn't get a fish that will outgrow your system until you actually get the upgrade.