When my son was in K he was a very advanced reader but didn't really care for fiction. Fiction at his reading level wasn't really of "age" interest to him either.
I took him and another advanced reader to the library for the teacher, and what worked best was they read every single Magic School Bus book that existed. (They were in their reading program.) I also bought or took from the library non fiction science books, on all subjects.
Fiction that did work, was stuff in more short story format. Encyclopedia Brown books turned out the be a huge hit in 1st grade. He also really liked the Geronimo Stilton (we called them the cheese books) series, and Captain Underwear. Potty humor at it's best, but very age appropriate.
Another big hit for this age was Joke books.
Edited to add.. what about puzzle books like Kids Sudoku, mazes. (Just not word searches.. IMO word searches are a waste of time.)
National Geographic Kids magazine. (Maybe you can find past issues in the library)
Don't forgot picture books. There are quite a number that have quite a high reading level because they are designed to be read to children by adults. I helped my son's teachers with tagging their libraries when my son was in K-3rd.
"How Droofus the Dragon Lost His Head" by Bill Pete. Or really ANYTHING by Bill Pete. It's a K-3rd grade level, but a high lexile measure and 48 pages with lots of text per page. He wrote dozens of books, all silly fun.
Last edited by bluemagic; 11/05/13 11:22 PM.