We have a little collection of examples in this article, "Columbo Flashbacks", in the Scrapbook area of the site. Some of them are about recurring locations, or callbacks to prior episodes, but some recurring props are here too:

http://www.columbo-site.freeuk.com/flashback.htm

I'm surprised I spotted such a relatively small one, but the thermos from SWAN SONG shows up in PUBLISH OR PERISH.

All the prop cameos just screams that there was one central prop department that supplied the show. Wonder how many were deliberate [mrs. Melville] and how many were coincidental [thermos] and how many were possibly just similar [the colt .32 auto]