There were many many different slogans painted on Soviet tanks and some were not even in Russian but in other languages used by people from this vast country! I think one can 'categorize' those slogans into 3 classes:
1. the patriotic type of slogan such as 'For the Homeland', 'For Russia',... to which one can add the ever popular 'For Stalin'
2. reference to real or legendary heroes
3. indication of whom donated the money to buy the vehicle (town, village, Kolkoze, factory,..)