This database is an excellent tool for book recommendations, and is made available by MeL to all Michigan residents free of charge.
You can do just the basic searches by keyword, author, title and series, and there are advanced search options by grade level, lexile, and much more. Entries include summaries and reviews, list awards (if any) and even suggest read-alikes. There are also recommended lists of books by grade level, topic, and genre.
Since this database is directly linked into MeLCat, once you find a title you like, you can request that it be sent to you in about 2 clicks. (See more below on how to requests books using MeLCat.)
The video below demonstrates how to do advanced searching by reading levels: