H - Where can we get the list? We have a customer asking for it. Thank you.

Some follow-up from Support:  in the design and reference guide it references Microsoft Fonts on page 591 found here https://docs.microsoft.com/en-us/previous-versions/windows/silverlight/dotnet-windows-silverlight/cc189010(v=vs.95)?redirectedfrom=MSDN#silverlight_fonts

In recent versions, one can use any font that has been installed in Windows on the OneStream servers.

The interface only lists a subset (which is larger than the one mentioned in previous comments), likely produced by standard Microsoft libraries; but any font can be invoked simply by using the FontFamily formatting property: FontFamily = [My Custom Font Name]