With the June Desktop update, we now support updating your chart fonts to any of the fonts we currently support for textboxes. Learn more in our blog: https://powerbi.microsoft.com/en-us/blog/power-bi-desktop-june-feature-summary/#fonts
We will be working on allowing you to use your custom installed fonts as well in a future release.
318 votesLaura commented
The limited family of fonts on Power BI means I can't follow my corporate visual guidelines even though our corporate font is included as standard in the other MS applications.
317 votesLaura commented
It's astounding that you can't set a workbook default font.