A tanker is a limited-role starship with the primary function of transporting large quantities of fuel and other liquid-state items. Loads can include deuterium, anti-deuterium and antimatter waste.
The Osaka-class starship served as a tanker, refueling other Starfleet starships in at least the 23rd century. (Starship Recognition Files 2)
The Emdor-class starship was an antimatter tanker developed by Starfleet in the 2370s. USS Ragronok was a ship of this class. (Trekker's Alternity Galactopedia)
In 2379, the USS Dauntless and a neutronic fuel tanker collided near New Gibraltar. (Star Trek: Dauntless)
The runabout USS Willamette served as a tanker for Peregrine-class fighters in 2380. (Star Trek: New Order)
The Kzinti tankers were used by the Kzinti to carry thousands of tons of antimatter at once. (RIS Bouteina: "The Whole Kitten Kaboodle")