The Good Place referenced Friends a LOT, but one particular time they gave a massive nod to Friends fans. During season four, Michael pleads with the Judge after her decision on human existence, and talks about the Friends members not getting into a good place.
Speaking to the Judge, he says: "Are you gonna sit there and say that every single Friend belongs in hell? I mean, maybe Ross and Rachel, and Monica and Joey, and definitely Chandler… But Phoebe?"
While this seemed just like an off-hand reference, fast forward to the penultimate episode of the series, and the group have made it to a good place. We meet Hypatia of Alexandria there, played by Phoebe actor Lisa Kudrow!