@Eklispe The problem is, I won't be relying on a definite system, so granting them better options isn't really something I can do. I want this RP to be player-driven when it comes to the growth of their character both physically and personally.
If a Goblin had a fixation on burning things, I would eventually grant him an affinity to learn fire-based magic which would allow him to transform into some sort of Hellfire Demon. What I'm trying to say is, the opportunities for growth that I'll grant to a character would be relative to the effort they give. If a non-humanoid and a humanoid traveled together and decided to explore a dungeon, the treasures they'd find would probably benefit the humanoid more than the non-humanoid. Jewelry or accessories might be open to either, but when it comes to weapons, armors, and the like, the choice on who it goes to or who'll experience some sort of power boost, is definitely obvious.