There isn't one. You can find a list, but it's guaranteed to be overpriced and the contacts will be outdated. Email lists have a shelf life, but unlike milk or bread, their vendors never rotate the stock. This means regardless of their quoted acceptance rate, you'll overpay for an outdated list. Your best solution is to source your own list, particularly in this niche market, through strategic and targeted lead generation campaigns. Save yourself the wild goose chase of chasing something that doesn't exist. I've purchased lists in niche markets, was quoted high acceptance rates, but after testing the emails against an email validation service such as BriteVerify, found the deliverability rates to be less than half of what I was promised. After running into this same problem more than once, I've developed various lead generation tactics to quickly identify and qualify high quality leads and I'm happy to discuss these with you.