Doo-dah, doo-dah... The dwarf planet Makemake has been found by Hubble to have a moon, meaning that all of the Kuiper belt objects identified as dwarf planets now have moons as well. http://hubblesite.org/newscenter/archive/releases/2016/18/full/
List of natural satellites and Minor-planet moon (both Wikipedia) all have lists of the known moons of the Solar System, and it's quite a lot. But from List of trans-Neptunian objects (Wikipedia), Makemake is the third largest known trans-Neptunian object after Pluto and Eris.