Yeah, I've seen a lot of it for two things.

First being sqlserver, though that's been able to run on linux for a long time now, there's a bunch of features not supported but not a deal breaker for a lot of people, I haven't encountered ssis or ssas in years for example.

Second being Internet Information Services (IIS), which some people really seem to like.

Wouldn't be surprised if active directory required a windows machine either, definitely a bunch of cases I'm not considering or aware of but I'm no sysadmin.