**This message and attachments were edited 9/9/2018 to expand the font character examples shown in response to Jonathan's message below.**
This attached Tableau Workbook shows a grid of the Tableau Online and Public browser-safe fonts (according to this font list: Fonts Not Displaying as Expected After Publishing to Tableau Public or Tableau Online | Tableau Software ).
This is also available to view and download on Tableau Public: https://public.tableau.com/views/TableauBrowser-SafeFonts/FontMenu
I have several times found myself trying to match a client-desired font, but need to know the space implications: Some fonts are wider, some are higher, some are more legible when the fonts are super small. I finally sat down and created a quick grid. This grid shows the browser-safe fonts in a variety of sizes, but all in the exact same space size, making it easier to compare and choose. It's also really handy to take to client meetings.
The attached workbook is a .twb because there is no data source. These are all text boxes.
Hope it's useful.