I would gladly bet on any sport as long as I get good odds and understand a minimum amount about that sport and the history of the players involved. You do not need to be a genius to research a players past history of wins/losses. Thats universal for any sport.
As far as to your question of specifically which sport which is not listed here that I would love to bet on:
Asian martial art/other fighting styles which are not that prominent in western society. Sumo, for example. In Japan, Sumo is a big thing and gets bet on all the time.
Regarding soccer, most of bookmakers and bettors use this word instead of football when they talk about soccer, because american football(NFL) is very popular among punters, and is the common word used to refer to this sport in the gambling world.
Really? I had assumed there was some high level gambling going on in the Sumo world because it is extremely prestigious and only for a rare priviledge of a select few members of the Japanese high society. Obviously at that kind of level I thought there would be some kind of gambling. And yes, while gambling is technically considered illegal in Japan, its not really illegal. It just has the image of being illegal. They still gamble.
Its a grey zone and they find many ways and loopholes around their gambling restrictions.
But basically what I meant is we need more exotic forms of sports gambling. And I see no reason why people from other countries in which gambling is legal should not have the opportunity to gamble on things like sumo.