[terom]

It is indeed very regional, e.g. the UK has its own thing going on with ring mains and fused plugs.

Over in my 230V corner of the EU, CEE 7/3 sockets are pretty much the only thing I'm aware of for new wiring, with the unearthed CEE 7/1 sockets still present in older installations. Both are rated for 16A, with either 10A/1.5mm² or 16A/2.5mm² branch circuits from the distribution board. It would be unheard of to wire those up with any higher ampacity at risk of overloading the sockets - although recent experience with e.g. EVs has shown that they're not actually suitable for sustained loads at 16A, given e.g. wear and tear on the sockets.

Unearthed appliances do commonly have CEE 7/16 plugs rated for 2.5A, particularly things like wall warts or USB chargers, which does fit into a CEE 7/3 socket.

I recall seeing CEE 7/16 (2.5A europlug) sockets, although those may have been imports from elsewhere in the EU. I suppose those would have the same issues if wired up to the same distribution circuits. But extension cables for those are rarer, the only ones I've ever seen are CEE 7/7 plug (16A) -> CEE 7/16 sockets (2.5A).

For residential/commercial loads over 16A / 3.2kW, it's all CEE / IEC 60309 connectors, and those are treated like distribution circuits with overload protection sized appropriately for the connectors/cables.