Some of the best options include Ashnod's Altar and Goblin Bombardment
So far, each battle has a specific subtype of battle called siege, so most of the rules we know specifically apply to those battles but may be different for future battle cards
And then you've got your sort of half-baked cards like Penguin Soldier
To determine a spell's total cost, start with the mana cost (or an alternative cost if another card's effect allows you to pay one instead), add any cost increases (such as kicker), then apply any cost reductions
1 Drana, Kalastria Bloodchief
Use Arena's Mana Average Calculator Another incredibly useful feature in Arena is that when you select "Deck Details," it will show you statistics about the composition of your deck