If you wanna stay with the classics, maybe: Great Expectations, Tom Sawyer, Moby Dick, Frankenstein
If you want similar modern books:
Firestarter by King was good that I read
The Martian Chronicles and Fahrenheit 451 are some modern classics like 1984
Jennifer Government is a very modern and polar opposite spinoff of 1984
The Brief Wondrous Life of Oscar Wao is gritty, award winning, and similarly themed to LotF