All four of my bikes have square taper BBs.
Three of them have Spa cranksets, and my main bike (Spa Aubisque) has Sora shifters.
My 1994 flat bar Marin Stinson has weird shifters. They are Shimano Deore XT flatbar shifters which work like dropbar shifters, you push the brake levers down to change gear!
The Temple has bar end shifters.
Nice - while I can appreciate the benefits of the Hollowtech system, the increasing dearth of cranksets available that suit my requirements in this format is certainly making me reconsider square taper (two of mine are already ST if not intentionally). Seems this isn't the only area where older stuff is becoming more appealing..
Didn't know about that shifter format; evidently didn't catch on although we're arguably nearly back there with some of the flare on gravel bike bars with STIs. How do you find them?