Just started reading through Brandon Sanderson's Mistborn trilogy and it feels tailor-made for a game adaptation where the player is a Mistborn for hire before the events of the first book.
Spoilers from the first book
The magic system is well-defined and the noble factions are all there with their own headquarters. Traversal would be the perfect hybrid of Assassin's Creed and Spiderman, running over rooftops and swinging from metal fixtures throughout Luthadel with iron and steel.
I imagine combat feeling like Breath of the Wild where the player can burn tin to slow down time, allowing the player to perform coin shots, dodge attacks, etc. Pewter increases damage and iron pulls weapons, coins, or enemies themselves if wearing armour. Zinc could allow skaa to be rioted, attacking nearby enemies on the player's behalf whilst brass could be used for stealth.
Areas the player could access at any given time could be limited via soothing stations and metal availability. The mist itself would even allow the developers to keep draw distance down and prevent players from travelling too far outside the city grounds until the story permits.