Fluent System Icons came to us.
I always liked the modern MS look and I always liked how nice the icons are in Microsofts UIs, but I could not use the MDL icons because of their license. Now that we have these nice open-source icons from Microsft we can combine them with their shiny opensource font Selawik and its on us to use these resources and build something nice.
If anyone would like to use them for React, I created a package https://yarnpkg.com/package/fluent-icons-react
For the C# devs, the Blazor package is in progress :)