I love Bi-Colors, although they are more of a midtank percher, I guess. You might try a
sailfin blenny or lawnmower blenny. Lawnmowers can get pretty big though!
You might try for a Yellow or Pink-Spotted Watchman Goby; they are pretty much bottom dwellers but aren't digging fools like Banded or Diamond Gobies.
Stay away from Scooter Blennies; really neat fish, especially the red ones but they are really in the "dragonette" class and like Mandarins have dietary needs that necessitate a large tank with lots of live rock or a fully stocked refugium for the big 'pod populations.
HTH,
Alice