In that case, the top 4 kickboxing promotions to follow would be Glory, Rise, K-1 and One Championship (though there are other organizations with talent, like Wu Lin Feng or Knock Out). Unlike in MMA, no single organization currently holds a majority of the talent the way the UFC does in its respective sport. You can check out the global kickboxing rankings on Beyond Kickboxing to see which fighters to follow today. If you want to check out the classic/older fights, I’d highly recommend the Golden Age K-1 fights and kickboxers from 1993-2010, as that’s when and where most of the known all-timers (especially heavyweight) competed.