https://openlibrary.org/ has quite a bit too, and is free to join. Don't know how old your kids are, but Robert Lawson is wonderful, though not so recently written. Historical fiction, I guess they'd be, as some of them are told from the perspective of the character's pet, like Mr. Revere and I. You can go on worldcat.org and find lots of history books and textbooks for children, sign up for free and preview them before you read them to your kids. If you have a middle school aged girl, she might like the Dear America series, historical fiction, but immersive, good for getting kids interested in American history and learning more.