Ookhtan non-Bird Tribes

[TurkeySloth]

I tried getting your imput on which humanoid races should become Fleetfeathers several months back to no avail. But, I decided to use an approached based upon tribes an color pairs yesterday. Thus, while the humanoid races will still become Fleetfeathers, there'll be other races as well. My non-Human selections are below because humans are meant to be universal. What races could fill in the missing pairs? Obviously, every race/tribe doen't need to have the ability to become Fleetfeathers. Naga appear in green, blue, and black because they're meant to be very low-population creatures, with guardians being benevolent and darks being malevolent. Thus, blue/black still needs its main tribe.

White/blue: Unknown
While/black: Unknown
Blue/black: Dark naga (non-Fleetfeather)
Blue/red: Goblin
Black/red: Demon (non-Fleetfeather)
Black/green: Drider (non-Fleetfeather)
Red/green: Unknown
Red/white: Dwarf
Green/white: Elf
Green/blue: Orochi/Snakefolk, guardian naga (non-Fleetfeather)

[Krishnath]

In White/Blue you could go with Vedalken, MTG sets have already shown they are prone to mutation (four armed in Mirrodin, six fingered in Kaladesh), so having some event in the past of your plane giving them feathered wings would not really be out of the question, and would give your world some added story flavor (however minor or major you want it to be). You could even bleed them into blue/black if you so choose.

[Lorn Asbord Schutta]

For Gruul maybe Ogres? They would compliment Izzet goblins as brute foils. They might even share origin, with both races diverging at one point. The smaller goblins had to survive using their wits - therefore they became blue/red - while ogres became more bulky, possibly preventing them from flying even when they spot wings.

For white black I would suggest Azra. They were put into black/red in Battlebond, but nothing stoping you from expanding their horizons. They could be people who dabbled with demons in the past and now they need to conduct their lifes to code of honor, lest they fall into mindless wrath and depravity.
Alternatively, archons, which would act as some aloof force of justice, similiary to Theros.

[TurkeySloth]

Thanks for the help thus far, guys. All of those are very good opions worth consideration. But, looking at the race/tribe list on MtG Wiki confirmed that Rakdos needs, at least, one more tribe because Magic's demons tend to be big scaries (black's iconic). While devils fit into that aesthetic nicely, I'm hesitant to pencil them in because it's likely to give the pair disctint striation between colors. ny better suggestions for Rakdos' main race/tribe?

What about Rakdos ending up with minotaurs and demons while Gruul ends up with centauts and ogres? That way Gruul compliments both Izzet and Rakdos.

[TurkeySloth]

The current breakdown is below. If I were to both replace orochi with naga and move guardian naga, what's the best place for guardian naga?

White/blue: Archon (non-Fleetfeather)
While/black: Azra
Blue/black: Merfolk (non-Fleetfeather), dark naga (non-Fleetfeather)
Blue/red: Goblin
Black/red: Demon (non-Fleetfeather)
Black/green: Drider (non-Fleetfeather)
Red/green: Ogre (non-Fleetfeather)
Red/white: Dwarf
Green/white: Elf
Green/blue: Orochi/Snakefolk, guardian naga (non-Fleetfeather)