2G
Lifegift
Enchantment
Whenever a land comes into play, you may gain 1 life.
Lifegift triggers off both players and Storm Cauldron affects both players. Yeah, it's 5 mana, but it has a built in Exploration effect. There's a card for RRR that lets you discard a land for damage. Means you probably need BoPs, but that shouldn't be a problem. Of course, with Storm Cauldron in play, a single Mountain can give you RRR if it starts the turn in play.