I'm not sure... but aren't there only a few different systems for feet?

back clamp - treadles
back clamp, low shank (very old singers)
side clamp, low shank (1900's singers and clones)

slant needle side clamps (Singer's slant machines, 301s, 400's, touch and sews, etc.) Anyone else do slant needle machines?

modern clip on (feet only, no shaft) (no shank on the foot itself, uses a 2nd piece that acts as the intermediary between the presser bar and the clip on foot.)

What other systems for feet are there?

There's the less common long shank - and I think Bernina has a configuration all their own. My vintage Elna (typical short shank) uses a new Janome walking foot, but can't use a Janome presser foot.

As you can see in my avatar, I also do slants. :) A 401 is what started my collection of vintage machines. :)

There are also the high shanks that are standard on industrial machines and some domestic brands. (Singer doesn't seem to have made any domestic machines with high shanks, but Kenmore did)

And there are also super high shank machines - all of them that I know of are Kenmores.

What a fantastic discovery!!

My best discovery was that my ancient old Singer buttonholer fits on my new Janome machine. It has a built in buttonholer but it won't stitch buttonholes that are extra thick or long. Most short shank feet and attachments will fit on other brands. The exceptions are Bernina and Husqvarna which only like their own brand and will not accept strangers.

Cool beans!!!