What about the EUR area ?
EUR (for EURope) is the code used for distribution in Europe. This code first appeared in 1994. its purpose was to gather several European countries in one single code, with an obvious goal: to simplify the distribution process. Yes, it is clearly easier to manage and distribute one single cartridge in 6 countries than 6 different cartridges in 6 countries, especially as most of the games were in English.
It's worth pointing out that EUR cartridges were aise used inside of FAH, NOE, etc. boxes. The EUU code can be seen as a EUR-esque code, as it had the same goal to gather several European countries under one single localization. lt only differs from the EUR code by the fact that it gathers a different set of countries.
There was a large variety of distributors for EUR cartridges, depending on the countries the games were sold in.
Did you know ? Tintin Prisoners of the Sun has an EUR box, but came with a NOE cartridge (no EUR cartridge is known to exist). This is the only EUR-boxed game without a corresponding EUR-labelled cartridge.