Dragon(bullet) goby, Amblygobius phalena, is a very good sifter, but they have a tendency to grab a mouthful of sand and hover over a coral to sift it.
The Valencienna sp gobies, diamond, golden head etc, are also good sifters who stay lower in the tank while sifting (usually).
Hectors and Rainsfords are much smaller gobies that lightly sift, and are not as easy to feed.
Two Spot gobies are smaller gobies that do very poorly in captivity in general.
All sifter gobys are proficient jumpers and must be in a well covered tank, or they will eventually find thier way to the floor. If I were looking for a sifter goby I would look at the Valencienna gobys, particularly the diamond or yellowhead.
My sifter, Valencienna sexguttata