Font prefixes #179

I have searched through the whole project and all issues and other sources but nowhere could find:

What are the prefixes to other fonts thant FontAwesome (fa-) ??
I can lookup the icon names on the respective font pages, but where do I find the prefix to use in Iconize?

I tried the following:
<iconize:IconButton Text="ion-stats-chart-outline" TextColor="DarkBlue" />

with or without "ion" prefix but it will always show the text instead of icons.
App.cs init and Info.plist setup is done according to the project homepage.

Thanks.