Open Foundry has spent over a decade curating open-source typefaces, showing each one with a proper specimen and suggested pairings rather than just a download link.
The curation is the point - it filters a messy corner of the internet down to fonts that are actually well made.
Use it when you specifically want an open-source font, one you can embed, modify, or redistribute, not merely anything labeled free.
Most fonts use the SIL Open Font License, which permits commercial use, but licensing is still set per font by its designer - worth a quick check on the individual font page before shipping it in client work.
