This is one publication, but it really does lean towards to large craft fairs at least when I joined it 9 yrs ago. I only kept my membership for a year. You can call your local Chamber of Commerce and possibly find some. Are you in a large city by chance? Where I live most markets have multiple soapmakers and some managers limit how many duplicate vendors they accept some do not. The best way is to talk to other vendors and ask them about markets, they are the one's that know. I am Not telling you to ask one of the soap sellers
. Vendors are really a fairly small community that tend to know each other, so spend some time visiting your local markets and talking to some of the craft vendors. Also look up Farmer Markets online for your area.
Another key to success in the vending world, make friends with the market owner, organizer or manager. The person/persons that handle the market on a weekly basis. Even if most vendors hate the manager/owner it is best to figure out how to make them a friend. Until the market fell apart my big Friday Night Market, which I attended for 5 yrs, had an owner that most disliked immensely, we actually liked him, plus his wife loved my products which I kept her supplied with. I had a prime location, middle of the street where the crafter's ended and the farmers began, plus he let me pay the 10% farmer rate instead of the $65 nightly fee. A market manager can also be a wealth of information about other markets. It is a small community for them and they almost all know each other
One word of advice do not expect to make great money, and it is hard selling just B&B and soap. There is a lot of competition and it is very hard work. I am fortunate that I have a fantastic market at a Kaiser Hospital and I am the only crafter allowed, because my crochet hats cater to chemo patients. Love it... Having to take care of parents every other month I cannot commit to weekly markets anymore. At least here, large venues do no necessarily mean lots of sales, the market I do is tiny and my sales consistently run much higher than any other markets I have done. My former Friday night market which was 4 blocks long, when I was attending weekly, was not as good as my tiny market.
Much good luck to you