These are the crme de la crme
Play boosters guarantee at least one foil, but compare play boosters and collector boosters, and you'll see the additional guaranteed foils help increase the cost greatly
Adagia, Windswept Bastion Applied Geometry Artificer Class Ashling's Command Brigid's Command Cabaretti Confluence Cackling Counterpart Caretaker's Talent Chandra, Flameshaper City of Death Cogwork Assembler Croaking Counterpart Dance of Many Dino DNA Donatello, Gadget Master Dutiful Replicator Echo Storm Electroduplicate Elvish Hydromancer Ember Island Production Esika's Chariot Esper Terra Fated Infatuation Feldon of the Third Path Flash Photography Ghired, Mirror of the Wilds Grub's Command Hazel of the Rootbloom Heat Shimmer Ignite the Cloneforge
Then if it has exactly four +1/+1 counters on it, search your library for a card, put it into your hand, then shuffle
Inferno Fist could also work, letting you keep the pressure on, while threatening to kill any Mutavaults that pop up