Here are two:
As a Captain, MG Raaen commanded one of the Ranger companies that landed in the first wave at Omaha Beach. Another member here was able to put us in touch and he signed and inscribed a copy of his memoir for me. He's still alive at 102, and in good shape from an interview he did a few months ago.
In their later years, John and Annie Glenn lived in the same apartment building in Columbus, Ohio, as my grandparents. John Glenn signed this for my dad, who later gave it to me.