Recs.
Updated
Flatpak is a system for building, distributing and running sandboxed desktop applications on Linux.
SpecsUpdate
Pros
Pro Wide variety of apps supported with easy graphical discovery & install
Flathub's repository has (at time of writing) 1082 apps available, including almost every popular linux GUI software I've ever searched for. It integrates into most linux DEs very well, and is fully supported by gnome-software, plasma-discover & others, allowing easy graphical package management in any DE.
Cons
Con Flatpak's sandbox is flimsy
While there are attempts to try and keep Flatpak applications secure, most applications have filesystem=host, filesystem=home or device=all permissions, which allows the application to write to the disk anyway, meaning that one malicious update to an application can lead to a major security issue.
Con Only for Flatpak-based applications
This software only works with Applications that support it.
They have a repository you can look at here: https://flathub.org/