Nigeria is the big one, but don't be fooled in thinking by doing that you will avoid a traditional Nigerian scam. A lot of Nigerian scams come out of the UK these days, so I would suggest taking Nigeria out of play altogether, but just be aware. I probably wouldn't take anymore out of play personally, but more keep my eyes open looking for any sus inquiries.
Scams can come from anywhere these days, even locally, so you can't simply isolate yourself from them by dropping shipping destinations. All that does is reduce your market size.