Are there any other sites like Google Fonts that let you embed fonts?

i don't have an answer, all i know is you need a huge bandwidth and lots of CDN to serve fonts.
exemple : the Roboto font was served 67 billions times during last week. And that's just one font among all of the Google Fonts.

But you can convert a TTF/OTF font to a webfont using this tool: https://www.fontsquirrel.com/tools/webfont-generator

Precision:
My previous comment was about free fonts.
Of course commercial websites provide what you're looking for, e.g. Linotype, Adobe,...