There's a lot more to salvage from "literature" but here's some inspiration from comic books :
Thorgal
Pitch :
Nordic mythology, mostly with a pinch of technology from long dead (except for two of them) humanoid aliens with god-like powers and a bit of central america's mythology (mostly Incas i think).
It starts with an exiled viking trying to survive with his family.
The universe would be very cRPG friendly with a vast bestiary starting with regular vikings raiders and going all the way to the mythic snake/dragon Nidhogg and harpies, ettins, centaurs on the way.
Lament of the forgotten lands
(poor title's translation attempt, as far as i know, it was only published in German, Dutch, Polish and French)
Pitch :
What happens after King Arthur dies (alternate names and it's a vastly different story from there) with only a daughter as a heir.
A mysterious dark uncle saves the day rallying the nobles but it turns out he practices dark arts and has a hidden agenda, the settings is dark fantasy with some really cool additions like a monk order focused on damage immunities (immune to regular weapons) said to be invincible (they're the good guys and they're not that invincible, turns out ... ).
As for books, many were already mentioned and i could add a lot more but the coolest one would probably be a
Discworld settings in a turn based isometric/top down TB cRPG but there's probably 0 chances of that happening.