Heavy tank
The Char 2C was one of the largest tanks ever produced. At the start of World War II, France and the Soviet Union were the only countries to have inventories of heavy tanks, such as the Char B1, T-35, and KV-1. The Matilda II was designed under the British infantry tank concept which is similar to the heavy tank having thick armor and weighing more than their other tanks. It’s usually separate because they have less firepower with their cruiser tanks (comparable to mediums) at the time having the same main armament but more machine guns. Later war examples were the German Tiger I and II, as well as the Soviet IS series. Note that "heavy" versus "medium" is more a question of tactical roles than weight; the Panther, for example, was a "medium" tank that outweighed most Allied "heavy" tanks.
Tank destroyer
The most famous Italian tank destroyer of the Second World War was technically not a tank destroyer, but self-propelled artillery. The Semovente da 75/18, based on the M13/40 frame, was developed to support front-line infantry, and therefore has fixed armament: a 75 mm gun in casemate. However, thanks to its low height (185 cm) and the caliber of its gun the 75/18 also had good results in anti-tank combat, fighting against British and American (but not Soviet) units. After the Armistice of 1943, the 75/18 remained in use by German forces until Italy's liberation.