Paying full retail for some of these wizards can be somewhat inefficient given their size, but thats where Stonybrook Banneret can save you time and mana
Naturally, The Incredible Hulk is ludicrously powerful, with Enrage to gain more and more +1/+1 each time he's dealt damage
Heartfire Immolator keeps the +1/+1 it got from Bronze Sword, even if it is countered
There are those that give card quality or draw cards, there are cards that do specific things while being on reasonably costed tempo dorks and there are powerful effects tempered by drawbacks that may be used to good effect in times of need
Its basically a free Negate in blue decks, and its a key card to win counter wars, stop your opponents turn-0 combos in many formats, or just protect a key threat you might have
At common, low-cost creatures with evasion are essential for building up your speed