ARCHIE'S LENDING LIBRARY AND BOOKSHOP,located in Karama has books for lending. BOOK CORNER on Dhiyafah Street has non-fiction, but I'm not sure about LL novels.
BOOKS PLUS carries paperback fiction and may have some LL.
BOOK WORLD located in Satwa has a lot of used books, so you might try there.
BOOK WORM on Al Wasl Road has as lot of childrens books...not sure about any LL books.
HOUSE OF PROSE in Jumeirah Plaza everything from crime novels to military strategy.
JASHANMAL located in the Mall of the Emirates has a lot of book/reading events with author appearances, but I'm not sure about LL materials.
VIRGIN MEGASTORE located in the Mall has a wide variety of bbooks.