It fits in an Energy deck, sure, but it can also go into decks with Experience, +1/+1 counters, and all kinds of other counters
Visit the Magic: The Gathering Foundations Card Image Gallery to see all the cards in the new set, including how to collect them in MTG Arena
Among commons, Pactdoll Terror shines brightest in blue-black, counting as an artifact to fuel Haunt the Networks drain effect while adding additional drains when the Thopters enter the battlefield
For a lot of folks, attacking isnt how Commander games end these days, which tells me that perhaps people need to be reminded about how to win games through the combat step
Others will be fantastically reimagined
The spell can't be countered if the mana produced by Cavern of Souls is spent to cover any cost of the spell, even an additional cost such as a kicker cost