>>15683182ONE is pretty cool. I went to one of their events live in Singapore when I was there for work and Shinya Aoki won a strap.
Nowadays it seems like most of the card is kickboxing for some reason, but I could be wrong. They also have grappling rules matches, so all in all it's a bit more interesting than the shit that passes for MMA you get in UFC.
Rizin is still my favourite just because I love the presentation and think that rings are much better than cages.
Rizin is the closest you'll get to old school MMA soulfulness complete with shadiness/possible organised crime involvement. ONE is not as soulful but I enjoy it more than UFC which I actually can't watch nowadays because everything about it pisses me off.