But despite the emphasis on spells costing four mana or more, I think that the most aggressive versions of UR are the most powerful ones, especially if youre not splashing in other colors
Unless youve got ways to place +1/+1 counters on Creatures, youre enticed to cast the Vehicle side Jetfire, Air Guardian first, as a 3/4 flyer that can Adapt 3 to become a 6/7 Flying Creature Youre effectively paying 7 Mana to get that 6/7 Flying robot, but you do have the option of removing those +1/+1 counters for colourless Mana
Plus other Amethyst cards, like Elsa, can help lock down your opponents
The spell lets you change the target of a spell or ability with another target
Thrasios, Triton Hero often chills in the command zone until you have infinite mana to feed into its activated ability so you can draw your deck and win with Thassa's Oracle, but you can also exploit the activated ability with cards like Training Grounds and Seedborn Muse