A couple months ago, Jon Gold wrote a fascinating article about his work at The-Grid creating “a system that can understand, select & apply typography with the nuance of an expert human designer.”
Unfortunately, Jon left The-Grid and never had the opportunity to take the work to production, so I copied him!
Here is a big ugly table with analysis of half of the Google Fonts in it. You can click on a font and the app will surface other similar fonts.
You can follow the instructions in the README to analyze the rest of the Google fonts (it only takes a minute, but the output is way too big for localStorage and slightly too big for the Github file-size limit).