What 'genre' is a film like 'The Man from Earth' and what are more films like it?

I just saw 'Mass' and the style of the film reminded me of 'The Man from Earth'.It practically feels like a stage play on film, and in some cases, I think they are adaptations of stage plays to film. Its films where the actors performances and the writing are doing 99% of the heavy lifting. The budgets are typically pretty tiny, the film is practically set in a single room with a group of characters that are strongly defined and have varying views on a scenario or differing backgrounds and they talk through a problem or circumstance, each giving their own unique and really well thought out perspectives that make the characters feel very real.What is the genre for a film like this? I want to find more but I don't know how to search for it.Here's a list of films that come to my mind:12 Angry MenThe Man from EarthMassCarnageI'm sure there's more I've seen but those are the ones that come to mind and damn, do I want more of it. I find them so captivating.EDIT: Adding these from suggestions for anyone that wants a list:SleuthThe Guilty via /r/movies https://ift.tt/G62vVCU