> I'd like to expand the font options for troff in my installation.
> How might this be accomplished?

I've kept your mail in my inbox for nearly a year because I'd been
meaning to look into this.  I finally got around to it and figured out
a method of sorts:

1.	Obtain postscript versions of the font.
	The file with the font data has the extension .pfa or .pfb
	The file with the font metrics has the extension .afm
	I tested on the following materials:

		http://mirrors.ctan.org/fonts/urw/garamond.zip
		https://www.math.utah.edu/~beebe/fonts/urwfonts-1.0.zip
		https://www.math.utah.edu/~beebe/fonts/utopia-1.0.zip
		https://www.math.utah.edu/~beebe/fonts/charter-1.0.zip

	Apparently there are tools to convert from other formats.

2.	Convert the font metrics to a troff font description.
	The attached awk script is something I hacked up to do this:

		convpsfont ugmr8a.afm GA	# URW Garamond
	
	This creates a file GA which should look something like this:

		name GA
		fontname GaramondNo8-Reg
		spacewidth 26
		charset
		!	26	2	33
		"	42	2	34
		&c...

	Choose a name not in conflict with those in /sys/lib/troff/font/devutf/
	Check the contents of this file makes sense; I haven't tested
	many fonts and my script may need adjustment or the output may
	need to be tweaked by hand. The troff font format is described in:
		/sys/doc/troff.ps!32
	The .afm format can be found at:
		http://www.adobe.com/content/dam/acom/en/devnet/font/pdfs/5004.AFM_Spec.pdf

	Put the resulting file GA in /sys/lib/troff/font/devutf/
	or else use troff's -F flag to point to the dir that holds it.

	You can now rm the .afm file or else keep it with its .pfa/.pfb

3.	Let postscript see the font.
	Put the font (.pfa/.pfb) in /sys/lib/postscript/font/
	I put mine in a subdir called useradded.
	Add an entry at the bottom of /sys/lib/postscript/font/fontmap:

		% fonts added by user
		GaramondNo8-Reg	useradded/ugmr8a.pfb

	Create a file called /sys/lib/postscript/troff/GA:

		0x0000 0x00ff GaramondNo8-Reg
		0x2010 0x2044 GaramondNo8-Reg
		0xfb00 0xfb06 GaramondNo8-Reg

	You can use other fonts for ranges missing from your font.

4.	Let ghostscript see the font.

		cd /sys/lib/ghostscript/font && mk

5.	Test.
		echo '.sp 1i
			.ft GA
			.ps 14
			Pack my box with five dozen liquor jugs.
			ø ß á ä à æ ¼ ½ ¾ © ¶ §' | troff | page

	ps2pdf will embed the font and make it printable everywhere.

Hope this is useful to someone,

Travis