Maybe if Deep Water turned all your lands into Islands, it would matter for cards like Engulf the Shore, Scourge of Fleets, or Vedalken Shackles
This one in particular deals damage equal to its power to a flyer that attacks you, but because it deals damage you can do all kinds of things with that, from lifelink and deathtouch to auras and combat tricks to force a bad attack
This whole interaction of shuffling your library after you play Brainstorm is very common, and one of the main reasons to play this blue spell
These Pokmon cards are harder to use but have some awesome attacks and effects, so if you want to put in extra the effort for a cool payout, Dragon types a sure-fire way to go
A typical mana curve for a Prerelease deck looks something like this: 1 Mana: 12 cards 2 Mana: 78 cards 3 Mana: 56 cards 4 Mana: 34 cards 5 Mana: 23 cards 6 Mana: 01 card and 17 lands