DD2 is too young,just what I read as a child:

Astrid Lindgren (author of Pippi Longstocking) has written several cute children's books that would be appropriate even for really early readers. I loved The Children of Noisy Village the most. I liked anything from Enid Blyton, I'm sure you can find all of them used from Amazon or ebay. Some of the others that are maybe more suitable for a school age child: Daniel Defoy Robinson Crusoe, Jonathan Swift Gulliver, Mark Twain Huckleberry Finn & Tom Sayer, Jules Verne, Narnia and The Surprising Adventures of Baron Munchausen. Erich Kästner books like Emil and the detectives (kind of like Famous Five) and Lottie and Lisa (the book behind the Parent trap movies).

For girls: LM Montgomery books like Anne of Green Gables, Louisa M Alcott little women etc, Mary Poppins for younger kids, Pollyanna is adorable too, Susan Coolidge Katy books, Johanna Spyri's Heidi, Jean Webster also has some.

Then if you search famous inventors like Edison from Amazon Children's book sections you can find nice biographies for elementary school aged kids. We used to read ton's of those too as a kid some of them were actually my fathers when he was a little boy.