Throughout the game, you will meet many lifeforms.
Most of these will be Gek, Korvax or Vy'keen, as the Sentinels (Aerons) wiped out almost all other life in the universe.
Below is a spoiler free guide to the main races & characters of the game. There is also a character called Telemon, who I cannot talk about without spoilers.
Recently, many more characters have been referenced, who may later make it into the game; including:
Asteria, Narcissus, Lazarus and Hildebrand.