Trying to name some more obscure ones that I love.

Tizonia is a CLI music player that can play music from your Google Music library. I like it bc I don't have to use a browser.

Pianobar is a CLI client for Pandora, but I can run this on a Mac too so not sure if it counts. Same no browser required benefit.

I love CLI music players bc they help you extend battery life vs browser based.

Gpaste is a clipboard manager. It even stores images copied to the clipboard.

Not sure if it counts but when I do a rectangle select screenshot in Ubuntu, it puts it in the clipboard (instead of putting a file on the desktop like Mac does) and then I can just paste it in the Jira ticket / GitHub pull request / Slack / etc.

Probably a bit more that deserve mention that I am not considering right now.