In Germany there is "Max Mustermann", which basically translates to Max Template-man. It's the default German name used for templates of official documents like passports and such.

In Arabic its “فلان الفلاني" “fulan al-fulany”, which roughly translates to “someone from some family”

https://en.wikipedia.org/wiki/List_of_placeholder_names_by_language

Japan, you usually use "Taro Tanaka" as the goto placeholder name. Tanaka is a very common surname here and it's super easy to write as well (田中). Sato is actually the most common but also a lot harder to write (佐藤). Tanaka is also a very "working class" name, it litearlly means "in the rice field" and most likely comes from families with a background of rice farmers. Taro also a very common given name; there have been quite a few Taro Tanakas throughout history despite being the placeholder name on most forms and the like. Taro, incidentally means "Big/Strong Son".

I am not sure offhand of a female equilvalent, it's usually Taro as the placeholder.

Hm, well about 40% of our population is named Nguyễn. I don't think there's an equivalent expression, but I'd choose Anh Nguyễn. In addition to being a name for both genders, 'Anh' just means something like 'sir' or 'older brother'.

In Norway we have “Ola Nordmann” and “Kari Nordmann”. Ola and Kari are pretty common and generic names. Nordmann literally means Norwegian, but can also be used as a last name.

We have the phrase 'every Tom, Dick and Harry' which is like that (UK)

If we're talking about a generic person it's usually Mr/s Smith or Mr/s Jones (near Wales)

France: Martin Dupont

But I prefer Dominique Dupont as the first name is both for men and women.

In my country (Spanish speaking) we say "Fulano de tal" Fulano is kinda like a template name nobody really is named like that. "De tal" really means something like "from somewhere".

We dont out it on the graves, but we use it as slang for situations where we need to refer to someone generic like "imagine a fulano de tal doing xxxxxxxxxxx".

There are other names like Zutano, Mengano, etc.

Edit: My mom sometimes uses "Miguel Perez". Those 2 are very common first and last names.

In Finnish it's Matti Meikäläinen for male and Maija Meikäläinen for woman. Matti Meikäläinen roughly translates to Matt Myself

In Vietnam, I think it's just most names 😂. Anh Nguyen is probably a good example. Most Vietnamese have the last name Nguyen. The national naming conventions rival that of religious families in the west. Think, Matthew, Mark, Luke, and John. Anh, An, Thanh, and Minh. Women are the same, but named after things considered beautiful, Tuyet, Hong, Pham, Van.

Funny enough, many names aren't always gendered, so I've met a decent amount of couples with the same first and last names. An Thi Nguyen, and An Van Nguyen is a couple that comes to mind. I dont have to worry about doxxing, since I bet that exists over 1000x here.

In Italy the template names are "Tizio", "Caio" and "Sempronio" whose origin dates back to the Middle Ages when they were used in legal cases as default names, probably inspired to the Gracchi roman family (Tiberius Sempronius Gracchus and Gaius Sempronius Gracchus). Another common name often used in examples is "Mario Rossi".

In US legal cases, "John Doe", "Jane Roe", and similar names are used for pseudonymized legal parties.

For instance, the plaintiff in the famous abortion case Roe v. Wade was one Norma McCorvey, identified as "Jane Roe".

A group of unidentified people appearing as plaintiffs or defendants may be called a group of "Does", from the name John Doe.

The words doe and roe both refer to deer, which are common wild animals in North America — and as wild animals, represent an arbitrary unspecified person. A doe is a female deer; and while "roe" can also mean fish eggs, roe deer is a common European species of deer.

Germany uses Max/Erika Mustermann – literally Sampleman. It's used for example on official sample pictures of our IDs. Some authorities in erlin have startet to use the gender neutral name Manu Mustermann.

Some others in the Anglosphere:

Fred Bloggs - no idea where it's from. Related to "bog" as in bog standard maybe?

Tom, Dick and Harry - is ages old. Even as far back as Shakespeare you can see the triplet evolving. "Tom, Dicke, and Francis" : Henry IV, Part I

In the UK it is Joe Bloggs

In Norway we have the stereotypical Norwegians "Ola Nordmann" and "Kari Nordmann". Ola and Kari were quite common names a couple generations ago (not so common now). "Nordmann" literally translates to "Norwegian [person]", but is also a not-too-uncommon last name.

We typically talk about them if we're describing something or some situation and what the stereotypical Norwegian would do/think.

In Spain we use "Fulano de Tal". It seems Fulano comes from the arabic language, meaning "Anybody". We use it when we don't the name of a person we are talking about, or we really don't care to know the name. Apart of Fulano, we also use Mengano.

Fulano/Mengano for men, Fulana/Mengana for women.

I guess our John/Jane Smith would be Pepe/Pepa García.

In the Netherlands there’s “Jan Modaal”, modaal (modal) referring the most commonly occurring value in or peak of a distribution. This name is used often when representing the experience of the most average Dutchman.

It’s especially often used in financial discussions and journalism, like “owning a house is getting further out of reach for Jan Modaal.”

Flemish talking part of Belgium it is Jan Janssen

Not to stifle further discussion, but this Wikipedia page has a wealth of examples

https://en.m.wikipedia.org/wiki/List_of_placeholder_names_by_language

Denmark -

Brian <- A name, but also a slur for people considered 'hillbilly'. Very frequently used against people who drive cheap tuner hatchbacks. Said cars can be referred to as Brian Cars.

Peter Jensen <- Also a name, but it's become notorious in Jutland because it feels like everyone is immediately related to someone with this exact first and last name.

Jhojho Aboolafya in everywhere in the Middle East I've been.