Drawing 6, 9, or even 12 extra cards by turn 3 or 4 allowed Blue to simply overwhelm opponents with resources
This helps dramatically with Emeria, the Sky Ruin and Emeria Shepherd, and Knight of the White Orchid and other effects that grab a Plains
If the cards on this list cant help you find the lands you need, Im not sure what else is going to do the trick
It can effectively shut down graveyard strategies in any format, from the Dredge deck of Modern to reanimator commanders such as Sedris, the Traitor King or Meren of Clan Nel Toth (and it can be cast for free in the opening hand)
Any combat with their stuff is going to drop that life total into a dangerous place
Most commonly found in Life from the Loam decks as a source of recurring card advantage