The Foredom H30 hand piece is the general purpose one that is included in most Foredom kits. It's a small, 3-jaw, (like our larger drill chucks)
Most of the others either take only one shank size or collets. I've put everything in the H30 from sanding drums, grinding wheels, (anything that fits in a Dremel) down to dental burrs in a variety of shank diameters.