Also Nix and Guix.
Re:Opera launches as a snap for Linux users
by AnIdiotOnTheNet on Friday August 03, 2018 @12:47AM
(#17677345)
Those are just package managers trying to be less crap than currently existing package managers. Vendors still aren't expected to create and deploy the application directly to the user.
Also, in that category, you forgot Gobo.
Application Bundles (GNUStep), AppDirs (ROX), Flatpak (formerly xdg-app), and AppImage (formerly Klik).
But Canonical invented a fifth anyway. Forgive me if I'm skeptical that change will actually occur this time.