You know, I actualy have a whole separate thread dedicated to “Whatever happened to” questions – it’s right over here!
But since you asked…
Prankster’s last canonical appearance was in last year’s New Year’s Evil special, where he continues to run a special service in Metropolis where he provides distractions for Superman while other criminals do their work, for a cut of the fee. He’s made some appearances since then in the digital Superman: Man of Tomorrow series as well – check out issue 13, and issue 20 (coming soon).
Tweedledee and Tweedledum were last seen in Batman’s “City of Bane” storyline from 2019, as two of the many villains working for Bane in his takeover of Gotham. Under Bane’s rule, and controlled by Psycho Pirate, the Tweedles worked as orderlies in his commandeered Arkham Asylum, beating sense into anyone who dared to resist him. Later, the Tweedles attempted to escape Bane’s Gotham with the help of Kite-Man and Scarecrow. But Thomas Wayne, working with Bane as the city’s new Batman, shot both of the Tweedles during the escape. Whether they survived this incident remains unknown, but because we didn’t explicitly see the bodies I’m going to wager they’re still out there.