using wind elementalAlthough primarily an offensive weapon, you can use tornado on your own team for a number of reasons, such as a last resort to escape situations (though your creatures/wizards will take damage on landing).
Another good tactic is to use it on some cheap and expendable creatures of your own team such as a group of faeries or skeletons , throwing them to the ends of the landscape and thus clearing significant amounts of the unexplored fog-of-war.
A further use is to utilise the functionality that when the creatures land, damaged, they then begin a journey back to the point from which they were thrown. This means you can throw a group of your own creatures out from a single point, who will then slowly return from the surrounding areas, closing in like a net! And if you used minotaurs who on landing would take damage and thus possibly become bloodlusted, they'll return really mad!