KDE neon is described as 'Ubuntu-based Linux distribution that offers a stable and easy-to-use platform, featuring the latest KDE Plasma desktop and application releases' and is a popular Linux Distro in the os & utilities category. There are more than 100 alternatives to KDE neon for a variety of platforms, including Linux, Self-Hosted, BSD, Mac and Windows apps. The best KDE neon alternative is Linux Mint, which is both free and Open Source. Other great apps like KDE neon are Ubuntu, Debian, Fedora and Arch Linux.
KDE Neon and Ubuntu Mate are both Ubuntu under the hood. KDE Neon has KDE's Plasma 5 desktop as a continuously updated component. Ubuntu Mate uses the Mate desktop environment, which is older, less fancy but more stable, reliable and faster on older computers. But the distros are fully compatible.