When I was learning the major system, most of the resources give letters as examples for the sounds that correspond to numbers, then tell you that actually, it's not really the letters that matter, but the sounds you make while you speak them.
I thought this was pretty annoying, since I never knew which sounds exactly correspond to which number, especially since multiple sounds sometimes correspond to the same number.
That's when I decided to put together this deck. It uses the IPA to show you the sound instead of the letter. But don't worry if you don't know how to read the IPA, there's audio included for everything, meaning you can (And probably should, for maximum effect) study this deck with your eyes mostly closed.
git clone https://github.com/b3nj5m1n/anki-major-system.git