It urgently needs an easy way to bring icons into the design. It should be possible to include icons like "material", "simple-line-icons", "lonicons", "FontAwesome" via a selection window. Currently, it is only very laborious about Illustrator.
Ryan D commented
If you create an XD file on Windows that utilizes icon fonts it does not transfer to Mac even though the other computer has the same icon font installed (you get a '[x]' in its place). Font icons are also not visible on the XD iOS app, which means you cannot test/demo the prototype. This pigeonholes us into using vector, which means we have to make up sizes for icons instead of letting the font properties to the work.
Font icons are a reality in web applications, they are not going away, and continuing to ignore them this is making our jobs harder, not easier. Thanks.