Can you make up a last name/surname that does not (yet) exist.

Yes

Surname

Maybe

@janbb and @SpatzieLover Is that Mr. or Mrs.?

Ebut.

Mrs. Augustlan

Pezdispenserheadsen
Vantemecula
Gruthorsen
Bankloren
Instrewk
Cawblern
Shienglade

I will be Mrs. Nina Shenlots.

Humpfurgelstien
Smileranthy
Blotherfurstinsky
O’Fannodigan
Klabberson

Mr or Mrs Lativa.

Anonymous

“Katzenundeichhörnchenvergewaltiger”

Soapytitwankspunkbubble

I have done that. I created a character name that got zero hits on Google and yet sounded plausible and not outlandish. I took screen shots of the Google results. And then I posted a little story excerpt using the name.

It took, as I recall, about two weeks before that name got hits on search engines. It had been collected in word lists, honeypots, and various other contexts.

If you post a name here now that gets zero hits, it’ll be crawled here and collected, and in a few days (I’m guessing) it won’t get zero any more.

Mister Vloktlmpxl

@SpatzieLover Surname, pronounced sur-na-mi?

Spankafoo Garaboowicz

Once a name appears on any site, it will become search able.

The name I used when I was a singer (and I still use online) was made for exactly that purpose. I already had a stage name, but once internet got invented I changed a couple of letters to make it unique (because it sounded too much like a certain car). I still get people confusing me with the car, but whatever google results you get is 100% me (even if it’s me playing a video game, posting on a politics site, asking for technical advice or having a drink at some old classmate’s party). And yes, it’s a plausible name, sounds sort of French, sort of Swedish, maybe Arabic.

You could take any name (or word) and change it like that:

Rebelovic
Janibbi
Spatzieloverofski
Amwiser
Raginolli
Freame
Zephyrou
Yarnmann
McJerub

etc

I got mine from a dream, @Jack79, but I like your idea. I have often found that one-letter typos produced fascinating variations on words that sounded like entirely authentic English.

Thing is, names are typically so weird to begin with, especially when you consider them globally, that almost any little change could generate another real one.

MormoravMIlo

Vrltyu

Zensky the Jewish Buddhist.

@zensky- I used to work with a Harris Zensky.