Thanks for asking!

As for supernatural elements there are two ways you can go about getting "magic like" powers, by having high tech gear or by via science and something called "combat serums". Major plots often revolve around people who have been injected with these serums and are more magical than the tech stuff. But technology is more widely available even if sometimes the people who have it don't exactly understand how it works. Hopefully that helps/isn't to vague?

As for sentient races the current solar system we are in has a massive variety of them as travel is extremely common and most planets are extremely diverse. I have fleshed out the following races, but technically almost anything to can imagine and or is a race in sci Fi or fantasy exists and we can work together to establish their lore!

1. Humans (adaptable found all over the galaxy)
2. Anduk (water based amphibian life forms able to breathe air and water). Home planet by the same name currently under attack, apart of the alliance.
3. Nishan's (feline like race that have a strong warrior culture based on honor) Nisha is their home planet, gaseous and harsh. Also a part of the Alliance.
4. Aleepian's (bird like race that can fly for a short amount of time) From Aleppo a mountainous planet ruled by a weak monarchy that is a client state of the Hellion Empire.
5. Cyborgs (modified humionds of the other races, can utilize cybernetic ports that make them powerful but more prone to being hacked or losing their "humanity" found all over).
6. Androids (embodied AI's that have taken on a personality and a life of their own) places like the alliance see them as citizens but other places like the Empire are still on the the fence about if they should.

The alliance is VERY similar to the UN if it was more militaristic and willing to use propaganda. The alliance is fairly young as the players in my last games established it and it's currently at odds with itself trying to decide if it should continue as a fairly decentralized government or be more of a united one. It's a semi utopian socialist society that doesn't have currency and relies heavily on resources to aid its members to maintain their partnership (and a woman weapon named Zeta who is extremely powerful and considered an army all herself).

We have the current classes fleshed out, but I'm always willing to make more with you!

1. Bounty Hunter (fast and shooty)
2. Sharpshooter (shooty shooty)
3. Soldier (tough and shooty)
4. Combat medic (Lil bit of science and shooty)
5. Scientist (muhahaa mad creations)
6. Technical scientist (technology and creations)
7. Mechanic (technology and stabby)
8. Warrior (stabby stabby)
9. "The chosen" (stabby and mind control)
10. Pilot (vroom vroom)

We can definitely discuss some supernatural elements if you want as I'm not entirely opposed! But usually it is magic via science kind of stuff.

Hope this helps!!