tan dolls are soooooooo hard to find - and harder to match "skintone" on.
In terms of commecially available in the US - there are the Monster girls, of course, and a couple of Bratz/Moxi girls who are "tan" as well - but they have the big heads. There was a tan girl in the Juku doll line...but I don't think those lasted long.
Expanding outside of the US there are tan dolls in the Takara Jenny line - some of them, like Julia, only come in tan, others like Miyuki come in regular and tan. The color doesn't match real well with anything available here - I know, I have some tan heads from that line that need bodies and I'm havingno luck
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Momoko also has a few tan options - but you are getting expensive at that point. Ironically though, the tan Momoko dolls tend to be easier to get and cheaper than the others - they dont' seem to be as popular in Japan.
Volks 1/6 dolls have tan options, but I'm not as familiar with them as the others.
Not a ton of help, but something to start with at least