Death Sauce. We once made a friend take a teaspoon without any kind of drink for 5 minutes for like 30 bucks. He ended up convulsing and sweating so badly. He had diarrea for 3 days. Not worth the money he contended afterwards.
One that you probably not heard of unless you are from the West Indian community.
Encona "West Indian Hot Pepper Sauce" - all varieties - the original and with papaya are my personal favourites. These are far better than anything I've tried in North America.
Matouk's Calypso sauce is the best I've tried this side of the pond.