I know that I would buy the following in 1/35 plastic if they were produced.
WWII era:
All of the American ones mentioned: T29, T30, T32, T34, etc.
T26E5 "Jumbo" Pershing that was going to be used for the invasion of the Japanese Home Islands.
M38 Wolfhound Armored Car.
A30 Challenger tank.
A43 Black Prince tank
A33 Excelsior tank.
Cold War era:
T92 light tank
Caernarvon tank
Conway tank destroyer
Saracen
Modern era:
Israeli Namer with Samson 30 mm RCWS option
Turkish Tulpar IFV
Turkish Altay MBT
ASCOD Pizarro/Uhlan IFV (I know Nimix out of Spain has a resin version)
Italian Dardo IFV
ROK K21 IFV
ROK K2 Panther MBT
Indian Arjun and Arjun MKII MBT
Jordanian Falcon Turret conversion or better yet complete plastic kit based on the demonstrator