Since the T-34 is there, I am assuming '39-'41 and possibly '42 vehicles would be in the early war. Thus, a representative sample:
Brit: Matilda II and III (armored, slow) and Crusader (less armor, faster).
Both with 2 lbr and 3inch howitzer variants.
French: Hotchkiss (?) 35 and/or 39 (37mm guns)
German: Pzkw38(t) or PzkwIII(E) (both w/ 37mm guns), PzkwIV(D) (low velocity 75mm howitzer)
Russia: T-26, BT-7 (very fast) (both with 45mm guns)
KV-1 (perked)
If '42 included, M-4 Sherman, M-3 Stuart and PzkwIII(J) (50mm gun).
If HTC can/will code vehicles with bow mounted main armaments:
US: M-3 Lee/Grant, Maybe a halftrack with a 75mm gun.
French Char B1-bis (perked for rarity)
British: Churchill MK1 (possibly perked due to heavy armor?)
German: StGIII(B).
To replace or suppliment the M-3, we should have a German SPW 251 halftrack (honestly can't remember the correct name for these -- I always called them "spitwads"), and a British Bren Carrier with a capacity of 5 troops.