mirror.cs.vt.edu is a public mirror archive for many lesser-known Linux distributions. This site strives to provide exposure to additional flavors of linux.
Community-driven free software effort focused on delivering a robust open source ecosystem around a Linux platform. https://www.centos.org/
A lightweight and flexible Linux® distribution that tries to Keep It Simple. https://archlinux.org/
A beginner-friendly Gentoo-based open-source Linux distribution. https://www.sabayon.org/
Debian-based Linux distribution geared towards various information security tasks, such as Penetration Testing, Security Research, Computer Forensics and Reverse Engineering. https://www.kali.org/
Ceph is an open-source, distributed storage system. https://ceph.io
A large collection of GNU and Open Source tools which provide functionality similar to a Linux distribution on Windows. https://www.cygwin.com/
A complete multitasking “UNIX-like” system available in both 32-bit and 64-bit versions. http://www.slackware.com/
A Fedora Special Interest Group that creates, maintains, and manages a high quality set of additional packages for Enterprise Linux, including, but not limited to, Red Hat Enterprise Linux (RHEL), CentOS and Scientific Linux (SL), Oracle Linux (OL). https://fedoraproject.org/wiki/EPEL
Manually browse the mirrors at your own leisure.