In The New 52 timeline reboot after Flashpoint, three different Clock Kings were shown existing:
Billy Tockman is an African-American crime boss based in Seattle. Tockman owns a nightclub called the Midnight Lounge, and vintage clock repair shop called the Clock King, which he uses as a front for his operations. [Green Arrow (vol. 2) #22] While Green Arrow is off dealing with The Outsiders, Diggle, along with Naomi Singh and Henry Fyff, talk Tockman into taking down Richard Dragon, to which he agrees. When they meet to take down Dragon, Tockman betrays them, claiming Dragon made a better offer. When Green Arrow returns and faces Dragon, he holds Naomi and Fyff at gunpoint on Dragon's orders and ends up shooting Fyff, then promptly getting beat up and knocked out by Emiko Queen.
Another Clock King, wearing the original Clock King costume, battles the newest incarnation of the Birds of Prey amped up on Venom.[Batman: the Dark Knight (vol. 2) #2]
Another, bearing an appearance similar to his Animated Series look (but with a black and blue suit and black and yellow glasses), referred to as Bill, tries to rob a store alongside his roommate Sportsmaster. He is stopped by Harley Quinn and Power Girl, but not before teleporting them into another dimension. He is shown to have the ability to rewind time. [Harley Quinn (vol.2) #11-13]