I want to find only fonts that support a specific language (In this situation, the language is Greek, but sometimes I want to find fonts that support French). Is this possible Thanks, y'all

Well, you can type some Greek text in the text preview field: [link]

You can do the same with characters used in French: [link]

For the fonts that support french, you have an option on this site : At the Preview line > More options > Only fonts with Accents

For langages that support Greek :
http://luc.devroye.org/greek.html