Google Fonts suggests syncing fonts to your computer with a tool called SkyFonts. However, if you're running MacOS and want to keep your machine updated with all Google Fonts without any extra software, you can do this with Git, thanks to the Google Fonts Repo.
To do this, run the following in your terminal:
cd ~/Library/Fonts/
git clone --depth 1 https://github.com/google/fonts.git google-fonts
Done! In the future, you can download new fonts by running:
cd ~/Library/Fonts/google-fonts && git pull && cd -
To take this one step futher, you can add the same command to your crontab
for regular automatic updates.
(Note: You can also do something like this on Windows, but as far as I'm aware, you need to actually install the fonts rather than downloading them to a fonts folder. So, after cloning the Google Fonts repo into a folder of your choosing, you would need to search for all *.ttf files and drag them into the Windows Fonts page in Control Panel.)
Thank you! Very useful.