The Tellati were a civilization that came into conflict with the Romulans at some point in the past.
History and specifics
During a battle with them, Donatra came across a Warbird whose command staff had perished. Beaming aboard with a couple of subordinates, she returned the vessel to the fray and launched a critical assault on the Tellati's flank. (TNG novel: Death in Winter)
One of the components to the second quadrant of Oblivion was a Tellati armory. (STA novel: Oblivion)