The Lyridians were an advanced species whose transgalactic star charts were among the most accurate maps of the known galaxy ever created.

In 2375, the Think Tank helped to return a Lyridian child's lost pet, a subspace mesomorph, in exchange for one of the charts. (VOY: "Think Tank")

This species was only mentioned in dialogue.
This species was located in the Delta Quadrant by the Star Trek Encyclopedia (4th ed., vol. 1, p. 492).