Starship-Integrated Auxiliary Craft
Starship-Integrated Auxiliary Craft are small craft connected directly to the hull of a starship. This is almost invariably to allow a vessel to carry a craft larger than would be practical in its actual shuttle bays. These craft are occasionally found in other settings, as well.
Captain's Yachts
A captain's yacht is a craft set aside for the personal use of a vessel's commander. In nautical history, such a vessel would be used to transport the captain between a ship at anchor and the port. In Starfleet practice, these are used for away missions deemed necessary by the captain, for diplomatic transport missions, and, occasionally, for recreational purposes, as Starfleet recognizes the enormous pressure starship command places on its officers. Strictly speaking, the 'correct' Earth naval parlance would be for captains to have "gigs" and admirals to have yachts, but Starfleet parlance uses the same terminology for both captains and flag officers assigned a vessel of this type.
Galaxy-type Captain's Yacht
California-type Captain's Yacht
Sovereign-type Captain's Yacht
Luna-type Captain's Skiff
Integrated Runabouts
Integrated runabouts are general purpose craft intended for extended away missions and planetary exploration. They are generally more capable than captain's yachts at these tasks, but are also less luxurious.