There are many different font formats and associated font file suffixes. A few that will be addressed here are:
PostScript® type 1 fonts. The .pfa is the Ascii form and .pfb the Binary form.
The font metrics associated with a type 1 font.
The printer font metrics associated with a type 1 font.
A TrueType® font
An indirect reference to a TrueType font (not an actual font)
Bitmapped screen fonts
The .fot file is used by Windows® as sort of a symbolic link to the actual TrueType font (.ttf) file. The .fon font files are also used by Windows. I know of no way to use this font format with FreeBSD.