Sometimes you just want a clean slate. The Quit Everything command kills all running applications, with any exceptions that you specify.
(quit everything) will quit every app that shows up in the Task Switcher/Dock except for Finder. It will not quit apps that are running in your menu bar or in the background.
To quit everything except certain apps, use
(quit everything except...) and include a comma-separated list of app names or bundle identifiers.
(quit everything except MailMate, Firefox, Xcode)
This command responds to some variations. You can
(kill all but iTerm) (burn everything except nvUltra, MailMate) (quit all)