Welcome!

And Dark Age nomads have cropped up in the discussion before, but prolly not if there are modern descendants.
As far as I know no modern people claim direct descent from any of the ones you mentioned, but I could be mistaken.
The problem is dual; on the one hand we don't quite know what kind of 'people' these groups were to begin with, and the national mythologies claiming descent have historically always been dodgy. (And don't really apply anymore.)
The Scythians seem to have been a varied bunch, looking at the evidence of their graves. The Scythians closest to Europe looked European and then they became progressivley more Asian looking the further east you got. It may have been a linguistic/cultural unified group, but more likely 'Scythinan' could be how the Greek lumped several people with similar culture/lifestyle (horse nomad)?
And the problem with the others is similar. The tentative identification of the Huns with the Xiung-nu (sp?) of Chinese history makes sense, but there is no conclusive evidence. And the Huns just disappeared, though I think there are parts of eastern Europe where local legend has tried to make a connection. ('Attila' is a pretty popular name in Hungary, but I would put that down to later tinkering with the Hungarian national identity.)
As for the Sarmatians, that's another shadowy group of horse nomads and no one really know what happened to them. In their case it's known that the Polish nobility in the 14th c. or so made up a myth of their own radical difference from the commoners based on the assumption that they were of 'Sarmatian' ancestry.
Goths: Germanic peoples are inherently tricky. There were so many of them. Part of the 'ethnic' identification is based on ruling dynasty. Culturally and linguistically they were all pretty similar, which makes one suspect the groups weren't that stable.
Historically the Ostrogoths after their defeat by the Byzantines in Italy just faded from history. The Visigoths set up shop in Spain, and the christian nobility after the Arab conquest still considered their ancestry Visigothic. Consequently one can find later Spanish examples of an emphasis of this link.
However, all the Dark Age Germanic people (ruling classes?) to hit Latin Europe left a legacy for the later nobility to pick up on. French nobles on the 17th c. would oppose their German origin (Frank, Norman) to the commoners (Gauls). Same could be done with the Langobards in Italy, and as stated, the Spanish had the Visigoths. The political decline of the aristocracy post-French Rev. pretty much ensured that this identification would be dropped from various ideas of national origin.
The Swedes during the 16th and 17th c. had an official national super-ideology of themselves as 'Gothic/Geatic' in the sense that Sweden was assumed to have been the origin of the Gothic people who conquered most of W. Europe.
At the church meeting in Basel in the 15th c. the Swedish bishop Nicolaus Ragvaldi managed to pursade the rest that Sweden deserved the seat of honour because his ancestors had conquered Europe. The Spanish did try to protest, using the argument that surely it was better to be descended from the people who conquered stuff, than from their cousins who stayed at home.

However with no real supporting evidence, 18th and 19th c. historiography pretty much concluded it was all myth anyway.
And no, I've never heard of the Jatts of Punjab, and didn't know the Pathans claim descent from some historical horse nomadic people. Looking at the Jatt link I get the impression they have some very 19th c.-esque ideas of origin and race?:confusion:
What I have read is that at least some of the Pathans serving in the British army in the 19th c. claimed to be one of the lost tribes of Israel, and Jewish.

That's kind of the point of mystic racial origin. You can change it to suit current needs.