The three modes are a bit disparate for my taste, but its probably worth it if you can snag the Stifle mode and make the other modes matter at the same time
Concordant Crossroads Granting haste to all creatures for only one mana certainly changes how many decks operate, but many players see this card as a combo-enabler
10 - Ozai, the Phoenix King (Borderless) - $20 This Ozai, the Phoenix King (Borderless) variant has striking artwork, the firebending keyword, and a high mana cost - but can be indestructible if you have enough unspent mana
But making a ton of creatures is inherently a win condition once you get enough of them, and the threshold for enough can be lowered very easily with any number of finisher cards
Nothing beats one mana exile at instant speed
No investigate is still in the game