I own an autographed copy of Outlander by Diana Gabaldon.
I also have several autographed copies of horror novelist Tamara Thorne’s work, but she’s a friend of mine so I suppose that doesn’t count.
Labrador Looks at the Orient, Sir Wilfied Thomason circa 1925.
Also, Somewhere in my book collection I’ve supposedly (according to my Grandmother) got the signed memoirs of the Captain of Nelson’s flagship who was once engaged to an ancestor of mine.