dmenu themed to fit in with GNOME's top bar.
Menu items are read from a menu.txt
file and the selected
menu item is executed as a command.
Enable Ubuntu's "Community-maintained free and open-source software (universe)" option in the Software & Updates app, then:
sudo apt install --yes git suckless-tools
git clone 'https://github.com/seanh/dmenu.git' ~/.dmenu
Then run:
~/.dmenu/dmenu-run-gnome