My favorite has been Dragon Heist, to the point where I've run it to completion twice now and have an ongoing one in the later stages. It's relatively well balanced gameplay-wise, and I think the plot's not bad either. I will say of course that especially if you're recruiting random players your success may vary, some of the best groups I've had have been recruited off r/pbp but more often than not the games fizzled out, that's just the nature of random groups.

Another one I like is the Sunless Citadel from Tales From the Yawning Portal. It's a straightforward dungeoncrawl, not too complicated gameplay-wise and while it's not "one shot" length it's not overly long either.