Besides Tuvax being eliminated in voyager
Best ‘best’ is hard to me to say; a lot of people don’t like, but i say “inner light”. As Picard receive the flute back and start playing, the emotional weight of the scene got me good.
The Inner Light was what finally got me into Star Trek.
It’s not like I had never seen an episode, in fact I’d seen lots, but it was comfortable background noise I’d change the channel too as yet another repeat I had no context for aired. Always somehow a filler episode or the second part of a multi-episode arc. I’d written off Trek as pleasantly mediocre and wholly dependent on technobabble despite otherwise being an extremely keen sci-fi fan.
Luckily, on some long forgotten forum, someone described an episode which sounded nothing like the Trek I had seen. As you said, the emotional weight got me good.