That may have been about all 2 of them then. I'm sure you can rig equivalent circuitry on others, but the 8080, 8085, Z80, and 6502 definitely did not have built in load mode. Only problem with the 1802, you can; just tie all data lines high or low - 00h is IDL and FFh is SMI (subtract memory immediate). NOP on the 1802 is C4h. 1802 was static CMOS process, so you could clock it right down to 0 and it would draw nanowatts until you started the clock back up again and pick up where it left off. It was also available in radiation hardened versions and saw duty in several OSCAR satellites as well as some space probes like Galileo. If you recall way back when they did a mission to swap out the computer on the Hubble telescope - I think the one they took out was a system built around the 1802.
I have a soft spot for the 1802 - it was my first computer, which I still have and it still works. But even earlier than that, it was an article on the predecessor chip, the 1802 (essentially the same but the ALU and registers were in two separate DIP packages instead of a single 40 pin DIP), in a 1974 Radio-Electronics or Elementary Electronics that pushed me towards the digital side of electronics. The article explained the details of the CPU's operation and though I was but 9 or so at the time, I read and reread that article until I understood it.