There are types A (Japan), B (US), C (EU), D (India), E (France), F (Germany), G (UK), H (Israel), I (AU) and so on: in which all have a distinct plug shape and differences in prongs. Type A plug is just two straight prongs without a ground while Type B is nearly identical to A but with a ground connection and Type F has no ground attached to the outlet while Type E does, usually this is solved with a adapter (for electronics that are dual voltage and support 50/60Hz frequency).
However, household appliances are typically region locked in the sense of being singular voltage (like electric kettles, toasters, refrigerators, washing machines) since those are intended to not be made for travel (mainly for domestic use supporting only a single plug type) unless you have both an adapter and a transformer. You can’t just plug a 120v 60Hz Toaster (B Plug) onto a 230v 50Hz outlet (Type F socket) with an adapter alone as that’ll blow the fuse.
Most modern electronics (as in laptops, game consoles and smartphones) support dual voltage and frequencies but their default plug type is region locked, so if you’ve bought a PS5 in the UK importing it into the US (the default cable is Type G that comes with the packaging when plugging into a TV) unless you swap cable for a Type B plug but it’ll work fine. Why is there no unilateral plug type that’s “region free” when discussing plug types found in appliances.
It was even worse at the start of the 20th century. There were no national standards, and different companies came up with their own plug/socket systems to save early adopters from having to wire everything in directly. If your house came with electrical sockets, their type often depended on what the builder could get cheaply. National standards arose when governments and standards bodies picked winners. (The US ended up choosing one American manufacturer’s flat-pinned system, though another one, with the pins rotated at a 45° angle, ended up being adopted in Australia, New Zealand and Argentina.)
Occasionally you see odd-looking sockets on old buildings, often with a distinctly early 20th century styling. Some places keep them for distinct uses (in railway stations in Britain you sometimes see sockets that look like the normal British ones only with the pins rotated, presumably reserved for cleaning equipment).
There have been moves to establish a unified international standard (which looks like a more compact version of the Swiss plug), though only Brazil has adopted it (and South Africa is transitioning gradually to it from the old British system it inherited).
And the reason few are changing it is because trying to change to a new electrical standard requires tons of investment to redo everything, and it’s a compatibility nightmare during the transitional period. … And all for pretty marginal long-term gain.
I think the rotated pins on British sockets is reserved for high-current appliances? similarly to how type L has an identical but larger 16A variant
There are higher-capacity versions of the plugs that are rotated, yes, but there are the standard 13A socket with the pins rotated to disallow usage of it to the general public.
Some systems have the earth pin shaped like a T instead