I'm going to go a bit esoteric here. Not sure he qualifies as a partner since he was Columbo's superior, and he only appeared once, but Captain Wyler who collaborated with Columbo in nailing Dale Kingston in the "gotcha" scene in "Suitable for Framing."
It wasn't a big role, but Barney Phillips was such a classic TV character actor that I always stop and take notice when I see him on a show.
His career spanned from the original "Dragnet" to the "Dukes of Hazards."
Fans of "The Twilight Zone" will remember him in that classic Martians episode and he played the original business partner of Miss Kitty in the 1/2 hour Gunsmoke episodes.
Yes, Barney Phillips was a terrific actor and I enjoyed him in "Suitable for Framing", along with the classic "Will the Real Martian Please Stand Up?".
Leaning towards Bob Dishy as Sgt. Wilson. Like his quirks and the way he may get under Columbo's skin at times but still helps him with is knowledge of latest techniques,etc.
Still can't remember about why his first name changed. I know there was a post a while back i'll have to look for.
Cool! I never heard of the reason and would be interested in reading about it.
I always enjoyed Bob Dishy, too, although his "investigatory procedures do differ somewhat from the Lt." Every time I see him on Law & Order I can't help but think of Sgt. Wilson.
I'm a little surprised Dennis Dugan as "Mac" hasn't been mentioned. Of course, that episode doesn't get a lot of affection, but I don't think much of that is due to him.