Crossover episodes have long-been a staple of network TV that seemed to peak in the 1990s (Golden Girls and Empty Nest on NBC in the ‘90s, CSI crossovers on CBS in the ‘00s, Scandal and How to Get Away with Murder on ABC in the ‘10s are among many other examples).
Crossover episodes have also occurred on cable TV, with The Walking Dead and Fear the Walking Dead on AMC and superhero shows on the CW.
But crossover episodes seems to be a strategy largely regulated to shows that air live / on network TV (and sometimes, rarely, between networks).
All that said, are there any examples of crossover episodes on narrative series (not reality shows) that originated on streaming services like Hulu or Netflix?