I have a bunch of novelizations but most I just collected for the picture inserts.
I recall the novel for Return of the Jedi had details on how Darth Vader was created after fighting with Kenobi and falling into a lava pit.
Princess Leia gets "raped" by Jabba the Hutt.
Alien the novel used the screenplay basis of the alien creating new eggs from its victims (which I like a lot more than James Cameron's ant colony approach).
I had the novelization of Carpenter's THE THING but seem to have misplaced it--Alan Dean Foster again I think-there was an extra character and more thing action.
I want to read the novel of JAWS 2-I keep hearing it is much better than the first.
I read The Godfather recently and it was so bad. I cannot believe how bad it was given the reputation of the film. Although it is said to have been written first--Puzo was talking with Paramount as he was writing it so I think he must have been hired by them--since they had made a mafia film THE BROTHERHOOD in 1968 which had a similar plot--a brother returns from military duty and is sucked back into the "family." There's no way Puzo was not aware of it. "Corleone" is also a name cited in the film.
I'd like to read the novelization of The Pit and the Pendulum from the Matheson screenplay but its so old it is hard to find.