Factions

Within the galaxy, there are more factions than just the republic as the republic may take up 55% of the galaxy, but there are other, smaller factions. Here is a detailed list of factions other than those of the republic.

T'Qar
The T'Qar are the only level 6 alien race humanity have come across so far. For a time the Arskodians and T'Qar were allies, but Arskodia was very wary of them as they would never go onto holo-calls or even send a still image. The T'Qar - Arskodia war began in 2641 when they invaded the Arskodian world of Lushertha.

Nobody has ever recorded seeing a T'Qar in the flesh nor have they ever recovered a full T'Qar corpse after a battle. The most the republic has are a couple bones here and there and drawings from people who have seen the aliens. All this isn't to say they haven't seen T'Qar ships like the slicers or motherships

Terran Federation
The Terran Federation are the old inhabitants of Terra and used to be the largest interstellar power before Arskodia. The Terrans would invite other colonies into the federation and claim they're not a dictatorship or fascist, but through how they conduct themselves proves otherwise. The Arskodians joined the Terrans for awhile and eventually confronted them about their functions the Terrans denied everything and applied sanctions to the republic, this led to the Arskodians attempting to leave, but being disallowed by the hateful "federation". These events led to the Arskodia Terran war and is why the Terrans now live in a network of space stations in the outer rim of the gamma quadrant. They remain constantly hunted by the Montergian Empire.