Are there any more free (born free) elves in Harry Potter? What is their place in the society? They have their own brand of powerful magic. What do they do for their living? Moreover, I find no reason for the house elves to be that obedient. Is it due to some spell?
Freedom was a punishment; we see the other elves in the Hogwarts kitchen look down upon Winky's behaviour (they roll her up in a rug, if memory serves). They were happy being servants and despite having powers that could easily best wizards, use them only in service (wizards enjoyed reciving the benefits of the power elves had, but wouldn't have tolerated it in a less meek and peaceful creature). They were generations in service, so it was very much instilled from birth what their place was. Most developed a love of serving (probably akin to stockholm's, to make the best of things, since there wasn't a way out either way)
They consider Dobby being paid insulting and stop cleaning Griffindor tower after Hermione leaves hiddlen knitted beenies around, trying to free them, which they find insulting (and it wouldn't work; Dumbledore is their master, not students).
If Winky's been freed as punishment, then there could be others, but they would be social pariahs. Most wizards wouldn't consider them an equal (Dumbledore is a special case, and considered crazy by some).
There may be some in Fantastic Beasts and Where to Find Them.
There are no other free house elves explicitly shown in the seven Harry Potter books, though it’s possible that a few of the Hogwarts house-elves may be “free” and adopted by Hogwarts the same way Winky was.
It’s possible there might have been some free house-elves in “Fantastic Beasts and Where to Find Them”. There we see five different house-elves - they’re identified as such in the published screenplay. One is working for MACUSA polishing employees’ wands, and four house-elves were at The Blind Pig; one serves Jacob at the bar, one gets Gnarlak a drink, one brings Gnarlak a document to sign, and one moves a crate of bottles. Whether any of them are actually free or not isn’t clear. It’s obvious, though, that the house-elves, especially the ones working at The Blind Pig whose personalities we see a bit more, aren’t nearly as respectful and subservient to wizards as the ones we see in Britain. One shows displeasure and reluctance at serving the bar’s customers.
Six shots of gigglewater and a lobe blaster, please.
The house-elf reluctantly shuffles off to fulfill her request. Jacob and Queenie look at each other. Jacob reaches out and takes one of the gigglewater shots.”
- Fantastic Beasts and Where to Find Them (The Original Screenplay)
Before that, the same house-elf made a brusque remark to Jacob (who is a Muggle, not a wizard) when Jacob seemed shocked to see a house-elf.
They’re also shown with jobs that might pay, such as bartending.
All of the house-elves in “Fantastic Beasts and Where to Find Them” (whether they’re free or not) are shown having jobs that could theoretically earn them a wage to live on. It’s unclear whether they actually accept payment, but they’re shown in jobs as opposed to serving a specific family. The house-elf at the Blind Pig’s bar is most likely the bartender, a valid job that could earn him a living wage. What the others’ job descriptions would be is less clear, but they’re all doing things that at least resemble jobs they could be paid for.
Even if those specific House-elves aren’t free, it shows house-elves would be capable of working in a less domestic environment, and in jobs other than cooking and cleaning.
I think it is quite possible that there a 'wild/free' tribes of house elves, but there is no cannon to back it. It is also possible that house elves were created by wizards, that would explain why they are so bound to them, and if that was the case I don't think there would be 'wild' tribes of them.
In canon, there are no free elves but Winky and Dobby, who work in the Hogwarts kitchens.
The house-elves are magically bound to be obedient. This is evidenced in the second book, when Dobby visits Harry, and he is forced by magic to punish himself every time he says something he shouldn't have, as well as in the fourth book, when Winky runs into the forest to avoid being hung high in the air, but she runs awkwardly, held back by the magic binding her to her master, who ordered her not to run.