These are all the races in the galaxy that have access to interstellar travel.
1. the Blobs
The Blobs were the first race to achieve interstellar travel. They used to be an almost humanoid race until they transformed themselves into slime that can live forever and are almost impossible to kill. The downsides of the transformation are that they are blind and can't stand up in normal gravity, however they can navigate by smell and echo location. Because they are completely synthetic, they can't reproduce naturally, so when a blob gets tired of living, it erases its memory and splits into smart blobs who are adopted and raised by whoever finds them.
Their bodies are perfectly adapted to life in space, so they all live on massive space stations controlled by a single, giant blob served by hundreds of smaller ones.
2. the Naiva
The Naiva are the third race to achieve interstellar travel. They used to be a barbaric warrior race who used their superior technology to conquer other worlds by force. They have now entered what they call an `age of enlightenment´. They now conquer by trading technology for a worlds loyalty. Their home world has been transformed into a utopia by using other worlds to produce all the goods and services they need, including slaves to do all the work that needs doing on their home world.
Because no Naiva has to work (apart form the leaders), they all spend their time on extremely time consuming hobbies.
They are very vain and are obsessed with looks and social status. They take manners very seriously and spend lots of time on empty pleasantries and politeness.
3. the Cidrons
The Cidrons received the technology of interstellar travel as a gift. They have gotten most of their technology in this way. The Cidrons are more attuned to emotions and spirituality rather than science. They are frail and physically weak, but have powerful telepathic and empathic abilities. They constantly send out subliminal psychic signals that make any creatures that perceive them as beautiful members of their own race. Because of this they are welcome pretty much anywhere and are very well liked by most people they encounter. Because they are frail and can feel the emotions of others, they dislike all forms of violence.
4. the Tripus
The Tripus got interstellar travel from from the Naiva, who wished to use them as soldiers. Despite their serpent like appearance, they are actually more like the octopus. They can move on land but need very humid air to breathe.
The trips love excitement and entertainment. They enjoy gambling, hunting and watching reality televisions, usually involving violence and death.
5. the Unifiers
The Unifiers got interstellar travel by assimilating a member of race with knowledge of the technology. The Unifiers have the ability to infect any creature they touch and transform them into Unifiers. They can also take on the appearance of any creature they've had contact with. Every cell in their bodies contain their memories, coded into strands of false DNA.
They assimilate every race they come in contact with. they claim that this is to create peace in the galaxy, but it is really in order to obtain all the biological and technological advantages of other races and become perfect.
6. the Oi
The Oi is the second race to develop interstellar travel. They are a mechanical race that has forgotten where they came from and believe that they were created by a machine god. They can transfer their minds between different mechanical bodies depending on their needs. They have used up all the material of their home world and there is nothing left of it. They travel through the galaxy in a massive fleet of spaceships.
The Oi follow the three laws of robotics, modified for a world of nothing but sentient machines.
7. the Cainians
The Cainians were able to capture the secret of interstellar travel from an enemy during a war. They were created to be the perfect warrior to fight off an enemy of a technologically advanced race. After the enemy was destroyed, the Cainians turned on their creators. They have great regenerative abilities and can regrow body parts. Cainians are militaristic in everything they do and are constantly angry, they are extremely pragmatic and have no sense of beauty. They need to constantly look for new enemies to fight or they will start fighting among themselves.