Stuka dive bomb. I almost never see it used, but it can deal so much damage
Reigel AT mines spell the death of any allied tank for 50 munitions
These two are great when used together. First you place quick mines on enemy teritorry and then you finish off immobilised tank with the bomb. Great against 85s for example. Also the mine is 60 munition.
Btw. these are both available in storm doctrine if sb needed to use that combo in 1v1 or random team.