You can also tap this for a mana and make two of different colors to cast a planeswalker
Self-Destruct, for example, would have been a nastier component of the already rampant Mono Red, especially with the knowledge that one of the winning moves for it was to blow up a Heartfire Hero using it
While a 6/6 creature is not all that imposing, Deep Spawn has the ability to make itself untargetable until end of turn for just a single blue mana, effectively has some form of evasion with the Trample ability, and also mills cards from the top of your deck in to your graveyard during your upkeep (which can fuel further reanimation shenanigans on future turns)
And it can also blow up in your face and cost you money
Pokmon booster packs contain cards, and their rarity level depends on what particular cards you come across in the booster
Blue mana offers Hullbreacher , a 3/2 with flash that can take the opponent by surprise and pilfer their extra card draws, turning them into Treasure tokens