Is there even a proper full size DC plug standard suitable for residential use? Besides USB I mean, since USB-C is designed for dainty little gadgets, not full blown appliances.
Maybe screw terminals would be ideal so you can cut your wall wart cable and wire it up. Most devices will have a bridge diode inside (total waste of electricity, but not going there right now).
I guess a cigarette lighter port could make sense but now we might be asking too much on the BoM.
Those little barrel jacks are fine for what they are, but I can't imagine powering a toaster oven with one. Cigarette lighter ports might fit the bill, at least mechanically. I haven't seen one of those in many years and forgot about them.
A kilowatt at 12V is going to be 85 amps and too hot for something rated for 15 amps.
Not sure what’s approved for DC use in general. Standards bodies will probably disagree with using something typically used for AC with DC because of the risk of plugging the wrong thing into it.
https://www.neutrik.com/en/products/power/powercon-20-a
https://www.te.com/usa-en/products/connectors/automotive-con...