All major factions have their own unique technology tree, the minor factions share a technology tree, and custom factions can use any of the technology trees. Clicking on the faction name will take you to more information about that faction, while clicking on the technology tree description will take you to the technologies of that faction.
Every race has access to the basic necessities of expanding and growing their empire. Everyone has some kind of factory progression, for example, and access to colonization tech for extreme worlds. They differ in many of the details, though, and each race has one or more areas of expertise according to their general personality and proclivities.