I use Libby with my iPad. Links to my library for thousands of ebooks and audio books. For older stuff that no longer has a copyright I use Project Gutenberg. Don't know what you like so it's hard to recommend. There are lots of sites that recommend books by genre. Depends on age too. Garth Nix is a good author for younger readers of fantasy. C.J. Cherryh is a great scifi author for any audience, but is more cerebral than most. Tony Hillerman writes mysteries that take place in the Four Corners area of the U.S. Robert E. Howard wrote the Conan the Barbarian series. Frank Herbert wrote the classic Dune and Robert Heinlein wrote Stranger in a Strange Land. There's the Percy Jackson novels and of course Tolkien. I just read a Patrica Briggs book. She does a lot of vampire and werewolf stuff.