Select a gauge and choose a Font under Appearance to restyle all of its text at once: the value, unit, label and dial numbers. Pick a single text element instead to give it its own font and Weight.

The menu holds around 40 fonts in five groups: condensed and display, sans serif, digital and mono, serif, and handwritten.

Other Google Font… takes any family from fonts.google.com by name.
Font on this computer… lists the fonts you have installed (Chrome and Edge on a computer). These show only where they're installed, so export from the same computer.

The Stamp editor has the same font menu.

Pick a font for your overlays: 40 curated fonts, any Google Font, or one installed on your computer.