Looking for more Core C# Classes like University.xamarin.com 101-109

I really enjoyed taking CSC 101-CSC 109 classes on University.xamarin.com.
For me it was a great refresher of the fundamentals for C# and few things I didn't know about.
Although there are some additional classes beyond CSC 109 on the University web site, I am looking for intermediate and advanced classes on the core of C#. Anyone know some resources like that?

Thanks so much,
Bruce