Fiction:DPSC

The DPSC, or Demonic Paradise Star Cluster, is a small star cluster, with a mere half-million stars within it.

Life
The dominant form of life in this galaxy is Mecholife, with the second runner up being silicone based, then carbon (biological) based and finally Extreme or Truly Alien Life (though the cluster contains some of all life types within it).

Mecholife
The (Class 6.9) is the main example of Mechological life and the only known mecholife civilization within the galaxy. There are many examples of mecholife in DPSC, as mecholife is among the most adaptable and invasive forms of life in the universe. Mecholife can actually alter itself and evolve to fit into any other category's natural environment. There is mecholife that exists in nebula, like an algae that feeds from the nebula gasses; mecholife that exists on superheated planets where common materials liquify; mecholife that can exist in the vaccume of space; and even mecholife that exists in the outer layers of stars. Mecholife's adaptability is due to being made of non-biological materials, but not any specific non-biological materials. However, mecholife can be determined as such by the distinctive (though subtle) thread-thin lines that cover their bodies and penetrate their very core. If it had little beads of dim golden light flickering across it's body along paths otherwise invisible, it's mecholife.

Silicolife
Silicone Life is the nearest runner-up to mecholife, being more common then stronger forms like metal-based and extreme life, but far more resistant to mecholife then biological life. There are eight Class 4 and three Class 5 examples of Silicone Life Civilizations in the DPSC, though none have attempted to communicate with or otherwise interact with non-silicone life.

Biolife
Biological Life, though common across the universe, has extreme difficulty surviving in this star cluster due to a lack of "habitable" planets. With so few yellow stars, there isn't much space for biological life to exist here. There are a few planets scattered across the cluster that can support it, but only one in 5 planets that can support it do support it. There are three examples of Class 4 and one example of Class 5 biological civilizations, as well as nine examples of pre-space biological civilizations. Biolife is probably the least common form of life, but not enough Truly Alien or Extreme life has actually been found to outnumber it yet.

Truly Alien/Extreme Life
Truly Alien and Extreme Life is easily the strongest form of life, but it is also the rarest due to it's unpredictable nature. The only known examples are a strange species of star-life that was found by accident when scanning a red giant to see if it could be used as a source of heavy elements and then a creature was seen living within the event horizon of a black hole. Neither entities could be seen by the naked eye; the star-life was made up of heavy elements and magnetic fields, the black hole entity was an organized shape made of nothing but gravity; but both were definitely alive (as they both interacted with others of their kind and with their environments) however it is not known if they are sapient or have civilizations.

Trivia

 * This star cluster is virtually irreverent to the universe.