The Percy Jackson saga has hit worldwide readership. Without a doubt, it's well-written, hilarious, exciting, and good for any age of reader. But what if you've read them all? What if you've devoured all of Rick Riordan's series?
Heroes of Olympus series and Magnus Chase series- Rick Riordan: These are the Roman and Norse continuations of the mythological theme Riordan has set up for himself. I know for sure that the Heroes of Olympus also features extended cameos from the favorites of Camp Half-Blood. If you'd like the try them out, here's the link for book 1 of the Heroes of Olympus and here's Magnus Chase.
Peter and the Starcatchers series- Dave Barry, Ridley Pearson: This adaptation of the Peter Pan legend is long, creepy, and beautifully written. A series that reveals the secrets of Peter Pan, Peter and the Starcatcherss is the beginning of a fast-paced adventure that will leave you eager for more. Click here to get a copy from the library.
There are really 3 separate series there, and many books in those series, so I'm going to leave it at that. For more recommendations, check out goodreads.com and type in the name of your favorite novel or author.