You hit my button with the hot pot. We've been travelling with one since it was required to sterilize baby items. Our hot pot boils, so in addition to what you and others have listed, we have done:
eggs can be hardboiled then chilled on ice and kept in a cooler a few days (I wouldn't keep them raw, but HB works well for a few days in a cooler)
mac-n-cheese boxes - here's the trick: sub a 5 oz can of (full fat) evaporated milk for the milk and butter that you won't want to keep in the cooler for a long time. Boil the mac, unplug hotpot, drain off water, add evap milk and powdered cheese packet. Can even add drained canned veg and/or tuna.
If you'll use it quickly, you can boil to cook "fresh" pasta, drain, and the heat in the pasta will warm the sauce. It's not hot but pleasantly warm.
You can do canned soups and stew in the hotpot as well if you have a non-stick bottom as do we. ...or use condensed soup: divide the condensed soup into disposable bowls then boil your water in the hot pot and add an amount equal to the condensed soup into each bowl - stir thoroughly to mix the soup and heat. Again, this is not hot but warm when done and it won't dirty your hotpot.
PM me if you want more ideas for a non-stick bottomed hotpot.
