I have seen every episode of Columbo countless times. I always like to recognize actors who are in several episodes, like Vito Scotti. Tonight (reading this site) I learned about Michael Lally who was in at least 27 episodes, but mostly in the background. One of my favorite actors in Columbo is Val Avery. His best character was Artie Jessup in "A Friend in Deed". He nailed that character.

Suzanne Pleshette and Val Avery were both in the film Nevada Smith.
Suzanne Pleshette and Val Avery were both in The Invaders, an episode called 'The Mutation'.

Another Columbo actors connection, when Val Avery married Margot Stevenson their best man was Rod Steiger.
Also, Val Avery's cousin wrote The Eiger Sanction.

Always enjoyed the episodes in which Avery appeared. He was definitely solid in his role as Artie Jessup. That entire episode (A Friend in Deed) had solid performances.