Data manipulation applications for life sciences data analysis, front ends to industrial robot automation systems, control software for medical devices, scheduling systems, ...
Sometimes there is still an inhouse C++ layer for driving the hardware when talking to older devices, but newer ones are covered by standard Windows APIs or OEM provided libraries, so we can write everything in .NET.
If you search for WPF jobs in Europe you will find many people do use it, even for greenfield projects.
I'm just curious because I always liked WPF but I don't hear about too many people developing for it these days.