For some of us in design or development, Fontmatrix has become an essential tool to manage large collection of fonts. While Linux Mint and Ubuntu development are making amazing progress, some excellent utilities that we rely on, such as Fontmatrix, are left behind. The packages for Fontmatrix did not make it to the newest repos.

Here's how I managed to get it working on Linux Mint 18:

Manually download Fontmatrix, Libicu52, and Libm17n-0:

libicu52_52.1-3ubuntu0.8_amd64.deb
From: https://packages.ubuntu.com/trusty/libicu52

libm17n-0_1.6.4-2ubuntu1_amd64.deb
From: https://packages.ubuntu.com/trusty/libm17n-0

fontmatrix_0.6.0+svn20110930-1.1build1_amd64.deb
From: https://packages.ubuntu.com/trusty/amd64/fontmatrix

Before installing each package, install the dependencies for each:

Libicu52:

apt install multiarch-support
apt install libgcc1
apt install libstdc++6
apt install libicu52
dpkg -i libicu52*deb


Libm17n-0:

apt install libfontconfig1
apt install libfreetype6
apt install libfribidi0
apt install libgd3
apt install libotf0
apt install libthai0
apt install libx11-6
apt install libxft2
apt install libxml2
apt install libxt6
apt install m17n-contrib
dpkg -i libm17n-0*.deb


Fontmatrix:

dpkg -i fontmatrix_0*.deb