Some fans call it a baby version of MTG, which kinda is, but thats nothing bad
Raph & Leo, Sibling Rivals Raph & Leo, Sibling Rivals have one of the easiest extra combat effects in the game, and untapping two attackers has a multitude of uses to make this exceptionally good for an easy to cast three hybrid mana
You can find MUL cards in all types of boosters (and they were even an important factor for why MOM drafts were great!), but Collector Boosters have a couple of exclusives
Here's my full review of the deck
The primary upside of this over Howling Mine is obviously that you get to go first, which is kind of like making it a cantrip, but its also worth noting that given the phenomenally clunky nature of spells in Esper Control decks, this might just make a reasonable instant speed threat to play at the end of their turn
The best thing about it: It does not need a single card from the restriced list