Source
Linux currently 29.1%
Sample size according to StatCounter: 24,353,436 page views
From Wikipedia, the free encyclopedia
Linux is a family of open source Unix-like operating systems based on the Linux kernel, an operating system kernel first released on September 17, 1991 by Linus Torvalds. Linux is typically packaged in a Linux distribution (or distro for short).
Distributions include the Linux kernel and supporting system software and libraries, many of which are provided by the GNU Project. Many Linux distributions use the word "Linux" in their name, but the Free Software Foundation uses the name GNU/Linux to emphasize the importance of GNU software, causing some controversy.
Community icon by Alpár-Etele Méder, licensed under CC BY 3.0
Those are somewhat niche distros, id personally recommend mint, zorin, pop_os! or what have you.
It really depends on what your usecase and tastes are though.
Niche is relative - they are variants of Fedora, and have been getting very popular very quickly.
Haven't you just recommended 3 stale Ubuntu variants there?
Miny and pop are often updated, zorin does admittedly have a slow update cycle