I've spoken many times before about various friends of Barbie or members of Barbie's family that have appeared in the doll line, but rarely referenced the even more vague lore subject of relatives of Barbie who have been named, but rarely or never appeared in doll form.
Most prominent would be Barbie's parents: her father George and her mother Margaret.
They have appeared in Barbie media like various Barbie books, the series Dreamhouse Adventures and referenced on Barbie's YouTube channel, but have never been represented in doll form.
Barbie's MOD-ern cousin Francie, of course, appeared in doll form, but she does canonically have named parents as well. According to a 1966 issue of Barbie magazine, her parents are Claude and Lily Fairchild.
Lily is apparently the sister of George, and married Claude Fairchild; but I haven't actually read this issue of Barbie magazine so I can't confirm that 100%. I'm going off secondary sources here. A magazine from 1966 is beyond my capacity to fact-check, sadly.
But Francie isn't the only canonical cousin, either. Max and Marie Roberts, twin cousins, appeared in the Barbie film Barbie & Her Sisters: A Pony Tale, and live in the Swiss Alps with their mother Marlene. Max and Marie had a brief doll appearance, in a tie-in product for the film.
But their mother Marlene did not. Note that Max and Marie are listed on the box as having the surname Roberts, meaning either Marlene is George's sister and kept her name and gave her children her name; or that there is an unseen brother of George who gave his name to Marlene and her children.
Here's Barbie, a book containing a series of short stories about Barbie and published in 1962 features a handful of other family members we have yet to see appear in doll form - Grandmother Rawlins (Margaret's mother), Lulu Belle Rawlins (another cousin) and the unnamed Mr and Mrs Rawlins all feature. Apparently Lulu Belle and her parents are from New Orleans!
No word on whether the unnamed Mrs Rawlins is either of the other aunts of Barbie on her mother's side (though they aren't shown with a daughter, or living in Louisiana, so probably not): Adele and Millicent.
Millicent, in fact, could not be much further from Louisiana: in her appearance in the film Barbie: A Fashion Fairytale, she lived in Paris!
Meanwhile, Adele appeared in an episode of Dreamhouse Adventures as an inn owner in Barbie's original hometown of Willows, Wisconsin.
Then again, characters move around all the time in the Barbie world, so you never know.
