I came across an early IBM PC ISA realtime clock/calendar card made by Quadram called the "Chronograph" (picture). It's basically the same clock feature they incorporated into their QuadBoard lines, but in a standalone form. What's odd is the metal card bracket is unusual and doesn't even fit into any PC case (no, not even a 5150).
I've never come across any other cards like this and haven't been able to find any other examples online. There are no enlightening special instructions for installation in the manual - it simply says "The Clock/Calendar may be plugged into any available slot in the Personal Computer." The only way apparently to use this card in a PC is to remove the bracket and put it in a slot just flopping around, maybe with a blank filler plate behind it. I can't imagine that was the way it was intended to be used though.
Any ideas about this?