Safe Octohax (become an Octoling; with/without broken octopus form)

Rank/Snail/Level/Money Editing Note: This older AIO doesn't set progress flags based on the new values. Instead, it sets the progress to max every time you make changes to your level/rank. This means you'll earn points as if you were Level 20+ even if you aren't Level 20+, and technically the value set is invalid. For changing stats (and other things), it's recommended to use the AIO GUI, which now also supports macOS.

All Gear, Weapons, and Minigames

Sisterhax (double Callie/Marie; from @Bkool999)

Colorizer (available separately)

Splathax (Windows-only, available separately)

amiibohax (Windows-only, available separately)

A few extras

Close any software and go to the HOME menu. Open up the Internet Browser and go to http://loadiine.ovh. Select "TCPGecko + Kernel", not "TCPGecko Installer". (If you are using the list view, select "TCPGecko + Kernel" from the dropdown box and click the "Submit" button.) The Internet Browser will start playing a video then crash. Open it up again and go back to http://loadiine.ovh. The Internet Browser will crash again. Go back to the Wii U menu and open up Splatoon.

If you haven't already, install Python 2.7. Downloads are located here. You will want the "installer" download for whatever operating system you have. Download Splat-AIO.zip from the link above and extract all of the contents to an empty folder. Run Splat-AIO.py. Enter in your Wii U's IP address and press ENTER. Make sure you're in Inkopolis Plaza in Splatoon. On the main menu, pick an option and press ENTER. Your selected option will then be executed. Go to the equip screen and back to the Plaza to see the changes.