Free sacrifice outlets are always strong, even type-specific ones, and Nemata lets you pull off dirty tricks like attacking with a board full of Saprolings, then sacrificing the ones that get blocked to pump up the ones that got through for extra damage
If you should decide to stick with your guns after those first games, Stella Lee certainly packs enough eye-watering combo power to hang at any power level
The next drop will come from cards like Gaddock Teeg, which have a lot of actual demand but which are mostly expensive because theyve only been printed once
Blue has some other notables like Moonsnare Prototype (great at enabling Winter Orb), Mnemonic Sphere (Japanese eggs really are the best), and Tezzeret, Betrayer of Flesh, but theyre a little more niche than what weve covered so far
Any removal or creature buffs which are cheap enough special shout-out to Dark Knights Greatsword for its free equip cost are equally useful
Zabaz, the Glimmerwasp | Illustration by Jason Felix In MTG, counter-movement cards are those that take counters from one permanent and physically move them to a different permanent