VitalizeutilityBudget$1.64This is the closest direct analogue: a green instant that untaps all creatures you control, letting you reuse attackers or tap abilities.
Benefactor's Draughtutility$13.02It untaps all creatures you control and can also draw a card, making it a stronger version of the same effect in many decks.
Seedborn Museutility$11.89Instead of a one-shot untap, it repeatedly untaps your permanents every turn cycle, serving a similar role in creature and tap-ability decks.
Quest for Renewalutility$5.77This enchantment repeatedly untaps your creatures on each opponent's turn once online, functioning like a slower, ongoing Mobilize effect.
Masako the Humorlessutility$20.33It doesn't untap all creatures, but it lets tapped creatures block, which is a similar combat-related green-adjacent utility effect for defensive play.
Voyaging SatyrrampBudget$0.16A cheap green untapper for lands rather than creatures, but it fills the same broader role of reusing tapped resources efficiently.
Kiora's FollowerutilityBudget$0.32It untaps a permanent, often used to reuse mana creatures or tap abilities, making it a flexible functional cousin to Mobilize in green decks.
MobilizationutilityBudget$0.90While not an untap spell, it supports the same kind of go-wide creature strategy by generating repeated creature presence after an alpha-strike plan.