Another class of effects actually come from lands and replace the destroyed land like Demolition Field, Field of Ruin, and Ghost Quarter, but I'll skip those for the most part on this list
To determine the total cost of a spell, start with the mana cost or alternative cost you're paying (such as a flashback cost), add any cost increases (such as kicker costs), then apply any cost reductions (such as that of The Wind Crystal's first ability)
Chaos: Whenever you roll Chaos, choose a creature on the battlefield
Rakshasa Gravecaller Exploit Spell & Mana Value: Moan of the Unhallowed, 4 Spell Versatility: High Like card advantage, adding significant board presence is always welcome
If you prefer your blue decks to involve the combat step, there are plenty of card draw engines to make sure the gas keeps flowing
Heads up