AppKiller lets you close all your open apps, with the fuss of going through them one-by-one. Do you want to be able to do with a single click? Or - even better - with a single... keyboard shortcut? Look no further!
Features
Easy-to-use: App Killer sleeps unobtrusively in your status bar and waiting for... orders
Ultra-fast: Killing all your open application will take no more than... milliseconds
Cmd+Shift+K: And that's all it takes to instantaneously kill all your open apps--really!
I purchased it as a "filler" whilst ordering some apps via Bundlehunt. In macOS 11.4 The App Launches and shows in Activity Monitor but doesn't pop up anywhere. I went to the developers web site and it has expired. Well, it was only a dollar
There are at least three self-review/ratings on this app.
Stay away from this company - They are not from the UK like their domain would like you to believe.
Just more get-rich-quick crap.
Although there are other free ways to force kill apps, it can be useful to do this with a single key. Meaning this app does what it claims to do. :)
A simple UI is something I always find important and this app fits the bill.