Chuck Norris
martial arts generally but from Asia(China, korea, ext) like jackie and jet I know no one will have the same style as jackie.KUng FU or martial arts generally.
If latter, DOnnie Yen? I haven't watched his movies in full yet, but they are on my to-watch list. He will star in Rogue One this year. I don't think he does the comedy side though.
https://www.youtube.com/watch?v=xQKb1CqIP08
I doubt anyone could replace jackie chan or jet li both legends in the game.
Tony jarr is the first person that comes to mind, still at 40 so can do much of the stuff but no where on the level as his first few films. Donnie yen is also 52 so can't do too much of the stuff he looked slow and old in ipman 3 or maybe they just speeded up pensioner mike tyson's hands and yens own movements for film.
Iko Uwais did an amazing job and is still young so has plenty of time and only 33.
So really its hard to say no ones really going to come close to the amount of films or work as jet and chan.
What about the guys from The Raid film series? Obviously not great conventional "actors" but phenomenal skills.
The problem with Tony Jaa is that he can't act. Jackie Chan and Jet Li have a more then enough to get by but Tony Jaa is a terrible actor with a squeaky voice. He was never destined for the global success that Chan and Li shared. IMO Jackie Chan will never be surpassed, he's one of a kind.