Angel of the Ruins Angel of the Ruins is a flexible card, both in the 7-mana angel and the cycling mode
As a bonus to Leatherhead, Swamp Stalker, it also has trample, meaning the chances of it dealing player damage as a 5/4 creature are already high, and that's before you put any additional counters on it.
Stormchasers Talent I like cards that give you a quick return, and with Stormchaser's Talent, we have a 1/1 prowess creature for only 1 mana
Part of a cycle that features the almost-as-broken Gaea's Cradle and somehow the hilariously unbroken Shivan Gorge, Tolarian Academy taps to make a mana for each artifact you control, which led to decks that would dump their entire hand of cheap artifacts, make a ton of mana by tapping and maybe untapping Tolarian Academy, and then use big card-draw spells like Windfall and Stroke of Genius to refill before eventually milling the opponent out with Stroke of Genius, potentially all on Turn 1
Whenever a new trading card game comes out, Im usually cautiously optimistic about its unique mechanics and design