@buttercupper

I know that dark wooden furniture in general is popular, although I couldn't tell you exactly why. Might be the homey aesthetic that it has, and/or maybe some people prefer to decorate with earthy colors.

Dark wooden chairs in particular are mostly found by unevolved pets, so it's possible that they're uncommon because most people evolve their pets, and therefore they're in high demand. I could be wrong though.

Or sometimes, multiple players happen to need something on the day that you decided to auction it, and you get lucky. xD

I remember having a legitimate war with someone when we were both looking for dark wooden chair auctions at the same time. I think it might've been Wayvern but I may be wrong haha

They fit pretty much any room aesthetically if you think about it, brown is such a neutral color when it comes to decorating your house ^^