But if you are asking about fonts that Imagemagick knows about for use by name, then use convert -list font to see all those fonts listed in its type.xml file.
If that shows nothing, then if you are on a unix-like platform, you can use the perl script by Anthony Thyssen to install your fonts into the type.xml file rather than doing them by hand. See https://www.imagemagick.org/Usage/scripts/imagick_type_gen.
Then doing convert -list font should list the ones that Imagemagick recognizes and you can then use them by name -font fontname . Otherwise, you need to provide the full path to the font file -font path/to/font.suffx.