Most of these races are actually inspired by years of Sci-Fi:
Assembly is based on the Borg from Star Trek;
Syndicate is based on the families from Dune;
Amazons are (I'm guessing) based on the artwork from the Heavy Metal magazine.
Oathbound Titan seems similar to Gundams and the Holy Mission motif is probably influenced by Warhammer 40K.
The Oathbound Seer's precognitive ability might be inspired by the 'Foundation' books.
There are probably many more influences and derivatives, but this is not a critique. They are indeed used in a creative way and are made to make sense to exist in the same universe. And it's fun (at least for me) to spot the references.
Amazons from heavy metal magazines? The Amazons of Planetfall belong to some of the most demures pure-women-societies in science fiction. For that I am thankful. I do not like oversexualized representation of both men or women. It often feels imature.
I would say the amazonians are more based on the dragon riders of pern or similar stories.
@Dreepa
Most planetfall factions are based off basic sci-fi tropes, but some contain cool little twists.
For example, the Kir'ko are inspired by various hivemind insectoid races (Enders game, Warhammer 40k, Starship troopers). But they have the cool twist, that they are actually an ex-hivemind, which is something that is very rarley explored to my knowledge.
Or the sharkan are the reptiloids who infiltrate various goverments. But they do this not in the present, but in the far future.
Or the Assmembly, who are cyborgs akin to the borg. But they are very individualistic.
Or the vanguard who aesteticly representing a humanity on its first steps between the stars. But instead of discovering the universe for the very first time, they actually do it for the second time.
Or the amazons, which could be considered a play with the enviromentally friendly noble savage species. But instead of rejecting technology, they very heavily and openly incorporate it into their society.
And instead of psionics enabling humans to reach a higher plain of understanding, or forming a united society of telepaths, the various syndiacte houses simply use their new powers to become an backstabbing and infigting class of aristocrats.
And the dvar are russians instead of scottish/scandinavians dwarfs...? okay not everything has a memorable subversion.
Yet I like these small twists, as they combine familiar tropes with a dosis of originality. Which is why I like the planetfall univserse very much.
It makes the different factions easy to grasp and understand, but also offers some new incentives to make them more, than just a copy of standard tropes.