The Omani were a civilization native to somewhere in the galaxy's Alpha or Beta Quadrants, residing in a region of space near the 24th century borders of both the United Federation of Planets and Romulan Empire.
History and specifics[]
The freelance freedom fighter Adrian Dareau and his group had a "little episode" helping the Omani in the 2360s decade, in or prior to the year 2364. This assistance resulted in the Omani choosing to side with the Federation rather than the Romulan Star Empire. (TNG novel: Survivors)