The Americans used .50cal, 20mm and 37mm for mobile AA. And as I said mainly on Halftracks. A very good Canadian design off the Grizzly (M4A1) called the Skink AA had Quad-Polsten 20mm cannons but was never put into full production.
There was an American design off the Grant chassis called the T36 with a 40mm AA cannon. I can't find a picture of that.
Another American design off the M24 Chaffee was the T77E1 which had a computing sight system and was armed with Quad .50 cal. There is a pic on Google images just type in T77E1 (As if you really care)
There was a British one based on the Light Tank Mk. II called the Light Tank AA Mk. II (Weren't we inventive) which had four 7.92mm Besa Machine guns.
Also one based off the Crusader III (Cruiser Tank) called the Crusader III AA. The Mk. I had the turret removed and replaced by a 40mm AA cannon. Mk. II and III had two 20mm Oerlikon cannon put in the turret.
There was also a triple-Oerlikon version which had the cannons in open turret. Only used for training though. I only can find pictures of models, for them.
There were some more AA based on tanks but I can't be bothered. The British tanks had a good personal AA defence when the crew could be bothered to fit it or get engineers to do it. Twin-MG which was two either Vickers or Bren wielded to one another then on to the tank.