One popular series of connectors for civilized AC power distribution that has not been discussed in this rambling thread comprises the "IEC C13/C14" connectors that are now ubiquitous on computers and test equipment that have a line filter at the power input.
These connectors are somewhat smaller in physical size than the NEMA connector of similar rating, and much smaller than the standard UK plug.
Normally, the appliance/equipment manufacturer fits a male connector to his equipment, and supplies a power cord (typically rated for 6 A) with the mating female at one end, and the national standard male plug (UK, NEMA, etc.) at the other end, to plug into the customer's wall outlet.
Before I retired, when we assembled systems for export that comprised commercial computers and monitors along with our own control and detector interface hardware, we used outlet strips on the console that had multiple female IEC connectors and one male connector. IEC C13 to C14 cords (readily available) were used to power the computers, and we then had to purchase only one specific cord to match the customer's country-standard outlet.
I assume that the specific size and shape of these connectors were chosen so that they were not identical to any single country's standard, so nobody could gripe about using a foreign country's standard.
My only problem with this was that use of that connector did not directly specify what voltage range (120 or 240 V) was intended, so some care in implementation was required.
As I remember, the only commercial equipment we supplied that was not usable at both of those voltages were some computer printers, which had to be ordered for 120 or 240 V specifically.