List fonts currently installed:

$ convert -list font

Install new fonts - for example:

$ sudo apt install fonts-dejvu

You then need to update the database used by locate:

$ sudo updatedb

Create a hidden subdirectory:

$ mkdir ~/.magick && cd ./.magick

Install a script from ImageMagick that does the heavy lifting:

$ wget

Run the perl script:

$ perl ./imagick_type_gen > ~/.magick/type.xml

And check the new fonts are present and correct by re-running:

$ convert -list font