This page describes some options to improve the font rendering on a fresh Debian installation.

Ubuntu has some rather good quality fonts, which can be installed on Debian. Have a look at https://design.ubuntu.com/font/ and search for “Download the Ubuntu Font Family”. Get the newest download link for the zip file with fonts. At the Debian system execute the following commands:

wget https://assets.ubuntu.com/v1/fad7939b-ubuntu-font-family-0.83.zip
unzip fad7939b-ubuntu-font-family-0.83.zip

Install a font manually by downloading the appropriate .ttf or otf files and placing them into /usr/local/share/fonts (system-wide), ~/.local/share/fonts (user-specific) or ~/.fonts (user-specific). These files should have the permission 644 (-rw-r–r–), otherwise they may not be usable. These mentioned paths can be customized in the fontconfig configuration file at /etc/fonts/fonts.conf – you can also include subdirectories or links, which is useful if you have a directory of fonts on a separate hard drive (or partition or other location). Run fc-cache to update the font cache (add -v for verbose output).

mv ubuntu-font-family-0.83/*.ttf /usr/local/share/fonts
chmod 644 /usr/local/share/fonts/*.ttf
fc-cache -v