Even when you can’t find them in Ubuntu Software Manager
Every once in a while, you’ll find you’ve got an application installed on your Ubuntu system that you can’t find in the Ubuntu Software Manager.
sudo apt-get remove <package name> will often work, but sometimes, the package name isn’t what you expected (Dropbox, or nautilus-dropbox, I’m looking at you.)
You can use dpkg to find out what the packages are named, couple that with grep, and you can often find the offending software:
dpkg --list | grep "package name"
Other package installers
I know I’ve run across applications that were installed via a different method than “apt-get”. I can’t remember which ones those were (think it was tying to remove an outdated version of Inkscape). Here’s a link I found how to uninstall Snap, Flatpak, and Synaptic. I’ll keep this for the next time I run into an application removal problem: https://ubunlog.com/en/desinstalar-aplicaciones-ubuntu-diferentes-metodos/
Next time came sooner than expected:
snap list | grep handbrake
sudo snap remove handbrake-jz