LA Opera's A Little Night Music with Judith Ivey, Victor Garber, Laura Benanti, Mark Kudisch, Kristin Bell, and Zoe Wanamaker. (What I would give for a recording of that production.)
RSC production of Othello at the Young Vic with Ian McKellen, Willard White, Zoe Wanamaker, and Imogen Stubbs.
Globe Theater's Twelfth Night with Mark Rylance, Samuel Barnett, and Stephen Fry (among others).
Hollywood Bowl concert version of Porgy & Bess with Audra McDonald, Brian Stokes Mitchell, and Wayne Brady.
West End Cherry Orchard with Judi Dench, Bernard Hill, and Robert Pickup.
The John Doyle revival of Sweeney Todd. Having the actors play their own instruments was a gimmick, but it worked because the actors actually played well and did really clear character work. When they died, they were witnessing Toby's story as he retold it in the mental hospital. There was a clear separation of what level the narrative was working on in any moment. It's not the only Sweeney Todd to reset itself in a hospital, but it's the only one I've seen that made it feel like a realistic setting for that story.
James Joyce's The Dead worked for the same reasons. That cast was always who they needed to be in the moment to make that story actually work as a musical.
I second The Pillowman. That cast was amazing.
One person show or not, I Am My Own Wife is still the most thrilling performance I've ever seen on Broadway.
—The LuPone production of Gypsy —The Color Purple revival, a week before the Tonys when Heather Headley had just joined the cast —The revival of Hello, Dolly! a week and a half after opening...incredible —Hadestown OBC
Navin Johnson said: "One thousand percent the cast of Shuffle Along -- thiswas especially apparent at the first preview, which ran nearly four hours because more characters received spotlight numbers (to this day I remain heartbroken for the unbelievably talentedFelicia Boswell, whose entire track -including aplum featured role as Josephine Baker -was cut before opening)
- Audra McDonald - Brian Stokes Mitchell - Adrienne Warren - Billy Porter - Joshua Henry - Brandon Victor Dixon - Darius de Haas - Amber Iman - Christian Dante White - Brooks Ashmanskas
It's a real shame there is no official cast recording, but the centennial of the original show is next year, so maybe a miracle can happen to get these people back together to preserve their performances."
I'm pleased to see several mentions of Shuffle Along because, while flawed as a show, it had a spectacular cast - and as it was first trip to New York City in a while, I had never seen any of them before. I've seen them since, of course. I saw it in midst of previews, so I know it changed a lot by opening (and had changed a lot since the first preview).
The cast was so astonishingly good that they elevated the parts that didn't really work and worked magic with the good stuff. Brandon Victor Dixon was particularly good and Adrienne Warren stole her part of the musical. But it's hard to single anyone out.
And then the next night, I saw Hamilton. That cast was pretty good too.
Others to mention: The original Broadway cast of Six Degrees of Separation was my first Broadway show, and the small cast (and, obviously, Stockard Channing) was terrific. And yes, I love the casts of Great Comet and Hadestown too.
The 2014 revival of Hedwig comes to mind, every single actor in the original cast won a Tony. The replacements were just as good, if not better (Taye Diggs being the exception...)
All joking aside (even though that is answer enough to your question because the whole cast was excellent), I loved the obc of In the Heights, Next to Normal, the 2011 Godspell, the 2013 Pippin, Fun Home, Come from Away and, most recently, the 2020 production of Company.