While certainly not one of my favorite episodes overall, I really like the opening in "Lovely But Lethal", partly due to the interesting camera work and lighting (but also because of Fred Draper's wonderful performance). It has a psychedelic vibe similar to some of the scenes already mentioned, though its manipulation of the camera and effects isn't quite as pronounced as some of the previously mentioned scenes.

It isn't especially strange, but the scene of the solarium at night in THE GREENHOUSE JUNGLE manages to be pretty spooky, and Arlene Martel really sells the ideas.

"The Most Crucial Game" has several scenes that are uniquely filmed, the most obvious being the murder itself, where there's not only a brief glimpse of Hanlon's approach from Eric Wagner's point of view, but also the use of slow motion in depicting Wagner's fall after being struck with the ice.
Another shot that's always been interesting to me is of Columbo and Hanlon ascending the escalator in the airport (of course, there aren't any actual effects involved there, it's just framed in an artistic way).

Also, in relation to fantasy sequences in the series, the scene where the noise of a game can be heard while Columbo sits in the empty stadium would perhaps be another instance of such a sequence (though obviously the effect here is mainly auditory).

I was going to mention the escalator shot.

Also in the airport, there is a pretty long uncut segment where the two of them are walking and talking while walking down the long airport corridor.

an interesting thing about that fantasy sequence is that in her imagination one of the detectives speaks in a very distinctive raspy voice. And then when the actual detectives show up and are asking her questions, one of the real detectives speaks in the same voice she imagined.

I love that a few folks mentioned escalator sequence...since I always thought it was cool...and wondered how many takes it may have taken to get the timing right

There's nothing silly or corny about the effects. They are highly effective and very much ahead of their time. The show would have been even better if they had continued to use them instead of falling into standard, formulaic setups.

Even though I don't hate "zoom" effects, one thing I've always liked about DAGGERS OF THE MIND has to do with the scene where Joe is leaning toward Nicky and Lily's car with that umbrella, and Nicky realizes it's Sir Roger's, and he gives that look like he wants to cry! A "zoom" would have underlined that too much, but without it the look he gives really creeps up on you. (Actually, I don't know how many times I saw the episode BEFORE noticing it.)

I'm confused as to who Joe is, but if it's Don Knight, he's an underrated gem. He was also the mechanic in Étude in Black who looked at Columbo's car and said "There are limits".

But aside from his two Columbo roles, he plays the lead alongside Laurence Harvey in the famous Night Gallery episode The Caterpillar. He is phenomenal. He pushes and provokes Harvey's lust to overcome his moral judgement and he causes a disaster in a way that only a true idiot can.

It was some of the most brilliant acting I've ever seen from both men and I highly recommend the 20 minute episode which is available on Hulu but not Netflix.

I haven't seen THE CATERPILLAR in a long while, but I kind of thought it was the same actor.