Flare of Denial $36.50 Surprisingly, Flare of Denial is the only entrant from MH3's Flare cycle of free spells to make the list, but its easily the best one coming out of the gate
(Limit: 2 per order.) secretlair.wizards.com Fuck you very much
Its an excellent tool in conjunction with physical products, especially as the pandemic winds on and playing in-person at your Friendly Local Game Store is nigh impossible
I have no problem spending bigger amounts of money on the cards if I can afford it (as long as Im not being ripped off) and I have no plan to flip the cards, at least within the next 20 or so years
It also has a mana ability for one generic, one green, one white, and one blue: Put Derevi onto the battlefield from the command zone
Tacking on a "mill four" to every instance of milling can be pretty big game