Rainbow Six instantly comes to mind as it's based on a Tom Clancy novel. Metro 2033 is a novel series too. Suppose you could count Dynasty Warriors too since it's based on ROTK.
The Warriors is based on The Warriors (1979) but it has a mode where you get to play some of the events leading into the plot and those hew a little closer to the 1965 novel by Sol Yurick.
Call of Cthulhu: Dark Corners of the Earth is a fun time, though it can be... Less than stable. Which, given that the development seemed like a Lovecraftian nightmare itself, isn't completely surprising.
It balances a feeling of powerlessness with moments to fight pretty well, in the beginning, but the back half kinda drops into a bit of a Power Fantasy.
The original metro 2033 is based on a Russian novel with all of its "both sides bad", Soviet nostalgia brainworms. The game is really good, despite being ideologically empty beyond "war bad".
The biggest ones that come to mind for me are The Witcher and anything Lord of the Rings or Harry Potter.
I know the SMT series was originally based off the Digital Devil novels, but kind of developed its own identity pretty quickly.
There were some interesting names in this list from Wikipedia I found.
Parasite Eve immediately comes to mind for me. But I’ve only played the first game. As far as I can tell it’s a more loosely-based interpretation with different characters and it was not done with the author’s approval, but I still really liked it.