Forum Moderators: skibum
Most companies use a specialist affiliate network. Check out the companies appropriate to your location. They should provide details of participants and a library of ad formats to put on your site.
CJ has a robust search function you can use after you join to search for merchants and/or specific products that may fit your niche. Not only that but if there are multiple merchants to choose from you'll be able to get stats to help you determine which have the best commissions and EPC (Earnings per 100 clicks).
I assume TD has a search function too, but am not familiar with their interface so don't know how well their search works.
Happy affiliate niche hunting!
Linda Buquet