Emerson, benchmade, protech, some older ZTs (emerson ones), some really old spydercos, southern grind, and some Les George use the same 3 hole pattern.
Spydercos seem to use three main clip styles and a few other less common styles.
The delica/endura, PM2, Para 3, Military 2 and a bunch others use the 3 hole hourglass. Then there is the wire clip and the triangle clip on the tenacious is found on a bunch.