The Vomnin Confederacy was an interstellar power located in the Gum Nebula. This confederacy explored space much as the Federation, but sought ancient technology instead of knowledge.
The starship USS Titan was the first Federation vessel to make contact with the Confederacy. (TTN novel: Orion's Hounds)
Titan again encountered the Confederacy, this time at the Axis of Time. Titan's crew did not trust the Vomnin to use the Axis responsibly and reported these beliefs to the Federation. This led to the dispatch of Department of Temporal Investigations special agents Meyo Ranjea and Teresa Garcia to investigate the Axis, and possibly stop the Vomnin from using it. (DTI novel: Watching the Clock)