Of course, I could have just looked at Seg-Assets/Fonts
Free for Commercial Use:
Cantarell: https://www.1001fonts.com/cantarell-font.html
CuppaJoe: https://www.1001fonts.com/cuppajoe-font.html
DejaVu Sans: https://www.1001fonts.com/dejavu-sans-font.html
Hussar Nova: https://www.fontspace.com/kineticplasma-fonts/hussar-nova
TexGyreCursor: https://www.1001fonts.com/tex-gyre-cursor-font.html
M+ 1c: https://www.fontspace.com/m-fonts/m-1c
Free for Personal Use (non-profit ok):
SF Laundromatic: https://www.1001fonts.com/sf-laundromatic-font.html
Where they're actually used in the game, unsure, and I do note some more fonts in the Source in a style sheet, but since that pertains to font families: "Tahoma, Verdana, Arial, Sans Serif", is more a choice based on what is on the player's system.