linuxfromscratch.org

linuxfromscratch
Building LFS teaches you about all that makes Linux tick, how things work together and depend on each other. And most importantly, how to customize it to your own tastes and needs.

tinycorelinux.net

tinycorelinux.net
Tiny Core, a unique and minimalist distribution of the Linux operating system and tools.

archlinux.org

archlinux.org
Arch Linux, a lightweight and flexible Linux® distribution that tries to Keep It Simple.