A couple of the sponsors on here have a good selection of CUCs. I ordered a crew from Reef Cleaners last summer and got way more than I expected - most people recommend ordering for a much smaller than you actually have. They're a mixture of ceriths, dwarf ceriths, nerites, and nassarius. Reefs2Go also have a good selection of crews that mix in red and blue hermit crabs among other things. Most of the members in a CUC from those vendors will be reef safe, but double-check what's included before ordering.