Rock 'n' Roll come immediately to mind - plays that wrestle with concepts (English identity and the diversities of passion) rather than the connect-the-dots plots of so many American plays.
I might place Javaad Alipoor and Kristy Housley's
Rich Kids: A History of Shopping Malls in Tehran very much in the "theatre as exploration of ideas" camp, and it does so very well. I hesitate to even call it a "play" in any traditional sense. Is it an experience? An interaction? Whatever it is, it is definitely a glorious surprise.
Honestly, I have found myself feeling less than excited about viewing theatre online the past year. For me, it so often highlights the fact that we can't all be in a room together creating and sharing stories instead of giving me the booster shot of theatre that I need and love. Plus, I am neither rich nor a kid, nor have I been to Tehran (I realize I don't actually know much about Tehran, or even Iran in general), nor have I been to a shopping mall in quite some time. Well, my uncertainty was totally unfounded.