I've listed several popular book series that are on a second grade reading level.
If your child's reading level is RM2 or RM3 (indicated on report cards), these books are the correct reading level.
Students should be able to read these books aloud with little to no help from you (unless there is a unique vocabulary like dinosaur names or exotic locations or Greek gods etc...)
A more extensive list can be found by going My Resources and clicking on RM2 Book List or RM3 Book List.