Whether its creatures that tap for mana, some absurd effect or just the ability to attack with abandon, untapping your stuff is very good
The idea of this, which isnt clear from the Illumineers Quest: Deep Trouble rules, is that you get a reward when you defeat Ursula for the first time
The final set of cards has Aspiring Champion, an amazing card for demon decks, and Let the Galaxy Burn, a new board wipe that looks decent thanks to the cascade trigger
Stubborn Denial has been a popular card out of the Steel Leaf Stompy deck as well as Izzet Ensoul Artifact decks as a way to defend against interactive decks, and it feels really good to see the sad look on your opponent's eyes as they helplessly bin their creatures while staring at the Stubborn Denial in their hand
Still, the power level is there, especially for Standard
And Lightning Helix is overrated