In the WMMA division, just a few women could hold the class of the GoT women. But no woman is as crazy as Queen Cersei, no woman is as strong and honourable as Brienne Of Tarth ( except Holly?).
-Maybe PVZ could be Sansa...
-I don't like Ronda, but if she was a lot more classy & smart, she could be Queen Cersei: Arrogant, ruled westeros years ago, be rektd by the New Faith (The Preacher Daughter) and publicly ashamed (Shame! Shame!) @193. Time will tell if she'll take back her crown (seriously doubt about that.)
-Holly could be Brienne: classy, honourable, silent knight, fought and won against brilliant knight (The Hound / Rhhhhonda)
For the men:
-Grey Worm comes to mind as Aldo (physicaly and they're both silent killers, like gamer007 already said)
-The Mountain / Robert Strong is obviously Bork: inhuman strenght, psycho look & not so smart. Plus, he's on something realllyyyy strong (thanks to Qyburn magic milkshakes)
-Roy Nelson is Robert Baratheon: fat, don't care, stupid death/KO. Hit first, then think (or never think, in fact). Farts, huge meals etc.
-Rose Namajunas could be a Sand Snake: High fight IQ, silent killer.
-Chad Mini Mendes could obviously be Tyrion but he is sooo dumb, unlike the Lannister, so no. Mighty Mouse is.
-Miesha could be Daeny: pretty, the voice of justice (against the bad Lannister/ Ronda). Good booty, and she both have Dragons/Boobs, wich is a big plus in the upcoming war.