Appimages
AppImage is a self-contained executable file that bundles an application with everything it needs to run (e.g. libraries, icons, fonts, translations, etc.) across different Linux distributions without installation. You just download it, and run it. Unlike Linux packages which are built for each distribution (and version) such as Debian; and must be installed using package management tools, AppImages are portable - meaning they can be re-used across OS upgrades or across computers.
Get App Images
https://appimage.github.io/ is a website listing available AppImages
I downloaded my first AppImage when I was using my favorite svg editor, Inkscape, and realized that the version I had was old, and that the latest version was not available "in the repos" for my Ubuntu workstation. When I went to get the latest version of Inkscape from the creators of Inkscape, I discovered that they had begun to package and distribute the software in AppImage format.
Desktop integration
Using AppImageLauncher, you can have system-wide management and integration of your AppImages.
You download it, verify the checksum, install it systemwide with dpkg and execute it from the command-line or just try to run the appimage which will now be intercepted by the launcher.

Problems
When I ran AppImageLauncher ~/apps/Inkscape-ebf0e94-x86_64.AppImage
I got
Setting _INKSCAPE_GC=disable as a workaround for broken libgc
You should not use AppImage in production, but you can speed up the AppImage by following this guide: https://inkscape.org/learn/appimage/