These are the superfamilies on Google Fonts. I’ve only included superfamilies where sans and serif typefaces are available, which have at least 3 styles per typeface, and which are not too decorative for general use.
Alegreya Sans
Alegreya Sans SC
Alegreya
Alegreya SC
Ancizar Sans
Ancizar Serif
IBM Plex Sans
IBM Plex Sans Condensed
IBM Plex Serif
IBM Plex Mono
Inria Sans
Inria Serif
Martel Sans
Martel
Merriweather Sans
Merriweather
Noto Sans
Noto Sans Display
Noto Serif
Noto Serif Display
Noto Sans Mono
PT Sans
PT Serif
PT Mono
Roboto
Roboto Condensed
Roboto Serif
Roboto Slab
Roboto Mono
Source Sans
Source Serif
Source Code Pro