Hey all! found a solution to this in another thread—basically go to the bottom of your site styles section and choose "Export Style Pack" (beta). open that json file in a text editor, do a find-replace for all the fonts you don't want (I'd leave safe fonts like arial maybe though) using your selected fonts as the replace. Save that file and then do an "Import Style Pack" (beta) of the newly saved file with just the fonts you're using.
Chances are a lot of the fonts you didn't want in the site are hidden blocks that you're not using anyway, so you will likely be safe replacing with whatever you consider your base or body text font.
Hope this helps—saved a TON of time creating unlinked pages and adding blocks to see where the leftover unwanted fonts were!
