With the release of Windows 8.1 came a little noticed addition to XAML called FontIcon. It is a rather simple XAML tag designed to show a glyph from a specified font. At the same time came two other tags in a similar vain (SymbolIcon which shows a glyph from Segoe UI and PathIcon which displays a path).
On it's own, FontIcon isn't extremely useful. Most of the basic glyphs are already part of Segoe UI and most of the other symbol fonts...