While it's possible to install 'KDE' software and Plasma desktop on most Linux based distributions, I have picked the distros which offer Plasma as their default desktop environment. These 'KDE-based' distros offer a better Plasma experience compared to those where you can 'also' install KDE.
At some point in time I have used each of these distros as my primary OS except for Mageia and Open Mandriva, which I tried but never used due to uncertainty around their future.