Yes, Forms. It is legacy, yet loved by many enterprise customers, lots of gigs available.
.NET Core will be relevant for our customers when it finally achieves 1:1 parity with .NET Framework features, until then not many will bother to rewrite their applications, they already have Java for non-Windows platforms with better libraries.
I had to port an application from .NET Framework to Java, because customer wanted it to run on Linux and .NET Core wasn't up to it, regarding the necessary features.