Hey Alicia, welcome to Fauna!
Although there seems to be a Canadian Board of Inquiry (Probably a good place to browse if you need some help finding "Good Guys". You definitely want to check reviews on potential buyers/sellers to make sure they aren't "Bad Guys") I don't believe the classifieds are sectioned by location.
If you're after an animal, but not interested in dealing with the whole importation thing, then I think your best bet might be to post a "wanted" ad in the section of whatever you're after saying in the title that you're in Canada. Vice-versa if you're selling in Canada only. Ex.-"WANTED: Breeding size female corn in Ontario" or something.
Otherwise a lot of people here are from the states and a few do import, check their Terms of Service on shipping and see. If you want to go that route, I suggest you do as much research as possible on how to safely and legally transport animals over the border, even if you're just a buyer, to make sure everything checks out~
Hope that helps,
Autumn