Looking for feat / trait / spell that will treat one race as another..,

[RigaMortus]

For example...

Start as Gnome but "mystery feat/trait/spell" will allow you to pick a different race dependent feat. Maybe Dwarf for example? Gnome player can use Dwarf racial feats (for example)...

I am aware of the Adopted trait, but it doesn't help when trying to qualify for spells or feats of adopted race, only other traits...

Any such thing exists? Or maybe some complex race/feat/spell combo?

[Master of the Dark Triad]

There's racial heritage, but that is only for humans (and anything that is part human, like half elf, for example).

EDIT: ^ That's a feat, btw.

[bigrig107]

Racial Heritage would work, but only Humans, Half-Elves, or Half-Orcs can tale it.

[Master of the Dark Triad]

And scion of humanity aasimars.