Excellent list. But don't forget the Killer Gals: Lee Grant, Susan Clark, Anne Baxter, Faye Dunaway & Janet Leigh. Leigh was arguably the most "sympathetic" Columbo Killer, as she was gradually slipping into dementia/Alzheimer's.
Or Helen Shaver who thought she had murdered Mrs. Columbo and tried to murder the Lieutenant also!
My parents returned from England in 1966 on the Queen Elizabeth. Oskar Werner & wife were on the ship also. I have a pic of the four of them on deck and at the bar.