AMX-50-120 Surblinde was a heavily amrored version of the AMX 50 with a 120mm gun in a conventional turret. Not built as a 120mm version of the oscillating turret was developed.
The Chasseur de Chars was a fast lightly armored tank destroyer equipped with a 90mm gun. Based off of the AMX M4 chassis.
The AMX M4 program was an attempt at replacing the ARL 44 with something more modern. The design was heavily inspired by the Tiger II. Three designs are known to exist, a 1945 design with a 90mm gun, a 1947 design and a 1949 design with a 100mm gun. None were built as the M4 program was superceeded by the AMX 50 program.
FCM 50 was another German-inspired tank with the same goal as the M4, making a more modern heavy tank than the ARL 44. Armed with the same 90mm gun as above tanks.
Italys' successor to the P26/40 heavy tank. Never built as the war ended before any could be built.
Proposed version of the P43bis with torsion bar suspension and the 53-caliber version of the 90mm gun.
The 14TP was an Incremental improvement over the 10TP light tank. None were built due to the 1939 invasion.
The 20TP/25TP were several designs for a medium tank in the 20-25t weight class. Armor was rather light and the tanks were designed with different 75mm guns, ranging from AA guns to field guns.
Here's the Panther II with it's proposed turret with the narrow mantlet and raised turret roof for mounting a rangefinder.
Two Swedish export designs with a 75mm gun.
British design for a tank with a 183mm gun in a rear-mounted turret based off of the Conqueror hull. Only a mockup was made.
One of several designs for the next medium tank. This one from Renault mounting a short-barreled 75mm gun.
Proposal of upgrading Pz 3 tanks with a Pz 4 turret and sloped armor.
Proposal of adding sloped armor to the Pz 4.
The T77 used the M48 hull with the T57s turret to mount a 120mm gun on a smaller, lighter chassis.
The T58 was a T57 with an even larger turret (largest oscillating turret ever had it been built) to mount a 155mm gun.