How many of the characters in the bible do we have enough evidence to show, at least in part, that they existed?
Lawrence Mykytiuk's book several years ago went through all the people who could be confirmed archaeologically, and is the most academically minded one I've seen so far, but he's recently updated the list and its in a more web-friendly format.
His book sets the limits (1250BC onwards) for who can be found. There's an argument whether the other people you've mentioned (Adam/Eve/Abraham) are actual people or just folklore/fictitious, but that rather depends on your level of skepticism.