Argos lets you write GNOME Shell extensions in a language that every Linux user is already intimately familiar with: Bash scripts.
These can be installed by copying the files to .config/argos after installing the argos extension itself.
This extension allows you to set fractional scaling factors using xrandr.
First you have to enable the experimental scaling feature in GNOME/Mutter:
$ gsettings set org.gnome.mutter experimental-features "['scale-monitor-framebuffer']"
Then install the extension and use the new dropdown menu on the top bar.
See also: