Hi Justin,

Thanks for another great recap on the latest Gutenberg plugin release!

There is also no visible way to clear the current selection and return to the default size.

It might interest you that there is a means of clearing only the font size selection, via the tools panel menu. When a font size has been selected, the corresponding item in the menu shows a minus icon, indicating the selection can be removed.

https://media.giphy.com/media/gckPAj4rZSzNqLtcpd/giphy.gif

Hope that helps!