What episodes would work well as community theater stage plays?
To elaborate on my criteria: these should be episodes that can work with a minimum number of sets, no special effect and modest-to-minimal practical effects, and amateur though dedicated actors.
Two examples come to mind.
The first is TNG’s “Measure of a Man”. This episode is almost entirely dialogue and takes place in large part in a single conference room. You could probably do a pretty straightforward 1:1 rendering of this episode on stage.
The second is DIS’s “Species Ten-C”, in which the crew make first contact with the titular species and determine how to communicate. This would require more creativity on the part of the production, but given that the 10-C communicate using light, I imagine that even an amateur production could do something compelling with practical effects.
I’ll admit that I am biased: I think I tend to prefer episodes that meet these criteria. I like my Trek talky and tend to have a soft spot for sappy and hammy episodes. But what intrigues me further about these stories is their ability to pass into cultural myth. I’m not saying that these are the only episodes that could transcend Trek and move into the cultural fabric of the era (think of Luke Skywalker and Darth Vader), but they seem like they might have the best shot.
"Waltz" from DS9 would work really well I think. If you cut out the b plot of trying to find sisko, you only need 5 actors, and it takes place in one cave. You could probably get away with one set, maybe two or three props, and no practical effects.
TOS: The Conscience of the King. The script feels like a stage play. There are no space battles or other big set pieces. It’s just people talking in different settings but it’s a gripping drama.
How about DS9's "The Wire". A powerful story of isolation, suffering, addiction, and the power of friendship coupled with medical professionalism. I have to admit I don't recall anyone else's role other than Dr. Bashir's and Garak's (and some momentary spots with Quark and some random nurse). I don't remember what the B plot was.
It’s definitely a polarizing episode, but I think it’s one of the strongest. It’s a better adaptation of the premise of Stephen King’s novel ‘It’ than many others.
The episode itself is primarily staged in an artificial environment that would lend itself well to a theatre set. It might be possible to reduce the number of sets on Voyager itself to one.
TNG’s ‘The Most Toys’ likewise principally takes place in a single room.
Well, the OP spelled out their criteria explicitly.
these should be episodes that can work with a minimum number of sets- In The Pale Moonlight could work on a single set. It's Only a Paper Moon could work with two. DS9 and holodeck/Vic's club.
no special effect and modest-to-minimal practical effects- In both cases the episode is carried out through dialogue.
amateur though dedicated actors- This one's a little harder to quantify, so I'll leave that up to OP's judgement.
In addition, they deal with themes that are relatable without being exposed to the context of the story. Moreso It's Only a Paper Moon than In The Pale Moonlight.
Ballance of terror would be great, I'd stage it with both bridges on stage, with the view screens facing each other center stage. while the action is happening on the enterprise have the lights on the Romulan bridge at 15-20% and vise versa. My production would sacrifice the surprise reveal in favor of some scenes on the Romulan bridge in act 1.