Rooted

• Linux Deploy – https://play.google.com/store/apps/details?id=ru.meefik.linuxdeploy
• Complete Linux Installer – https://play.google.com/store/apps/details?id=com.zpwebsites.linuxonandroid
• DriveDroid – https://play.google.com/store/apps/details?id=com.softwarebakery.drivedroid

Non-rooted

• Debian noroot – https://play.google.com/store/apps/details?id=com.cuntubuntu
• GNURoot – https://play.google.com/store/apps/details?id=champion.gnuroot
• KBOX – http://kevinboone.net/kbox.html

Stand-alone

• Ubuntu Desktop on Nexus 7 – https://wiki.ubuntu.com/Nexus7/Installation
• Ubuntu Touch: Installation – https://docs.ubuntu.com/phone/en/devices/installing-ubuntu-for-devices
• Ubuntu Touch: Porting to a new device – https://docs.ubuntu.com/phone/en/devices/porting-new-device
• Ubuntu ARM – https://wiki.ubuntu.com/ARM
• Arch Linux ARM – https://archlinuxarm.org/
• Debian on ARM – https://www.debian.org/ports/arm/