Lord of the Rings, if read with an elder person.
Outlaws of Ravenhurst... TOTALLY, GREAT BOOK!!
Chronicles of Narnia, obviously...
Boxcar Children & Bobbsey Twins are children's mystery stories, very family friendly
first one stars 14 year old and 6 year old boys, Henry and Benny, and their siblings 12 and 10 year old Jessie and Violet
2nd one is slightly more complicated
there are Bert and Nan, 8 in one edition and 12 in the other
and Freddie and Flossie, 4 in one edition and 6 in the other
Agatha Christie for teens (older teen side)...