well, harlequen tusks get about 10" long and are going to start bothering others in a tank of that size.
All in all, a 60g isnt that large and many marine fish need a larger tank. Any type of fairy or flasher wrasse might be too passive when placed with a yellow, which are supposed to be a bit more aggressive.
Any wrasses from the genius Pseudocheilinus would probably be okay, as the fish in your tank can hold their own. I personally love my yellow watchman goby, which would be another choice. small gobies are fun and colorful, and dont add much bioload. Blennies would also be a good choice.
other fish I can think of are hawkfish, firefish, cardinals. Hawkfish are semi aggressive to aggressive, while cardinals and firefish are extremly peaceful. I would be careful if you want firefish, they are jumpers and are very easily bullied, though my three are definetly worth it, they add lots of color to my 75g display.
