You can try the Chronicles of Amber. There are 10 books but they are not heavy. The first five I adored. The later five where not bad either, but they were a tier down compared to the first.
The Earthsea books by Ursula K. LeGuin, fantasy
The Foundation Trilogy by Issac Asimov, science fiction
The Discworld Series, by Terry Pratchett.
Fantasy, Magic, Wit, Humour, Philosophy.
Pratchett uses an imaginary world to make observations about this one. The stories are good too, and have plenty in them to keep you smiling. Start with "The Truth", then "Going Postal" - after that read them in any order. There are about 50 of them.
The Black Company series by Glen Cook.
The " Pendergast " series by Preston and Child. Starting with The Relic ! Really good series of many books. I've read them all and they're great stories.
The Chronicles of Narnia by CS Lewis