Generally speaking, there is not much popularity for the games that I am interested in in my area. I am not a big sports fan, however I am a great fan of NASCAR, MMA, and volleyball. If you have any good ideas, let me know.
NASCAR is enough familiar with crypto. I have several times read the news about NASCAR which has sponsorship by crypto like bitcoin and dogecoin. But as you said, I don't find many betting sites that listed NASCAR, maybe have several sites, but didn't accept crypto as payment. About volleyball where you have mentioned too, I ever seen volleyball women listed on betcoin.ag and stake. Maybe if you have a time, you have to look it again.