Plasma/Live Images
Try and install Plasma from a live medium provided by several Linux distributions.
Shipping the latest code from Git
KDE neon
KDE neon builds Frameworks, Plasma and Applications on a continuous integration system.
You can use the Developer-stable version for builds from Plasma/5.x branches or Developer-unstable version for builds from master branches.
openSUSE
Krypton is an installable live image based on openSUSE Tumbleweed with the latest KDE software from Git master (unreleased) on top.
See also https://en.opensuse.org/SDB:Argon_and_Krypton
Ships Plasma 5.16
KDE neon
KDE neon builds Frameworks, Plasma and Applications on a continuous integration system.
The User and Testing editions have Plasma 5.16
Kubuntu 19.10 Eoan Ermine (development builds)
The Kubuntu development release daily iso builds now have Plasma 5.16.
http://cdimage.ubuntu.com/kubuntu/daily-live/current/
openSUSE Argon
Argon is an installable live image of openSUSE Leap with the latest Plasma release. See also https://en.opensuse.org/SDB:Argon_and_Krypton
OpenMandriva Cooker
OpenMandriva is a desktop centric, completely Plasma focused, distribution. Cooker - the current development branch - includes Qt 5.13, KDE Frameworks 5.59, and Plasma 5.16.2.
Ships Plasma 5.15
openSUSE Tumbleweed
In addition to Git based versions there is openSUSE's rolling distribution "Tumbleweed" which ships the latest Plasma release tested with openQA:
Both 32 bit and 64 bit versions are available.
Slackware
Alien BOB (Eric Hameleers) provides an installable Live image for Plasma 5 based on the development tree "slackware64-current" and the liveslak scripts. Login account/password are both "live". Use su or sudo to become root (using the "live" password).
Manjaro
Manjaro KDE Edition is rolling release distribution. It provides the latest stable Plasma, KDE Applications, KDE Frameworks and Qt releases.
https://manjaro.org/get-manjaro/
Kubuntu
Kubuntu 19.04 Disco Dingo, released in April, includes Plasma 5.15.4. The live ISO is available for download.
KaOS
KaOS is a sophisticated Distro, which focuses completely on KDE. A modern packaging approach leads to stability and freshness at the same time. Small and helpfully community.
OpenMandriva Lx 4
OpenMandriva is a desktop centric, completely Plasma focused, distribution. The current stable release, 4.0, includes Qt 5.12.3, KDE Frameworks 5.58, and Plasma 5.15.4.
Ships Plasma 5.13
GeckoLinux
GeckoLinux is built directly from openSUSE packages and uses openSUSE repositories.
GeckoLinux NEXT Plasma includes the Plasma 5.13 desktop environment on top of the Leap 15.0 base system. It also includes KDE Applications 18.04 and the KDE Framework at version 5.47.0.
http://geckolinux.github.io/#download-next
GeckoLinux ROLLING Plasma can also be updated to Plasma 5.13.
http://geckolinux.github.io/#download-rolling
Kubuntu
Kubuntu LTS 18.10 Cosmic Cuttlefish, released in October, includes Plasma 5.13.5. The live ISO is available for download, and Plasma 5.15.4 can be installed via the Kubuntu backports PPA.
Ships Plasma 5.12 LTS
KDE neon
KDE neon builds Frameworks, Plasma and Applications on a continuous integration system.
The User LTS edition builds from Plasma 5.12.
openSUSE Leap
The latest released Plasma LTS version is available as a live image with openSUSE's stable branch "Leap":
GeckoLinux
GeckoLinux is built directly from openSUSE packages and uses openSUSE repositories.
GeckoLinux STATIC Plasma includes the Plasma 5.12 LTS desktop environment on top of a Leap 15.0 base.
http://geckolinux.github.io/#download-static
Kubuntu
Kubuntu 18.04 Bionic Beaver, released in April, includes Plasma 5.12 LTS. The live ISO is available for download.
Ships Plasma 5.8
Debian
Official Debian 9 “stretch” live images can be downloaded from debian.org/CD/live. There’re several desktop environment flavors, including KDE. The next version, “buster”, will ship Plasma 5.14.