Selvala, Heart of the Wildsramp$11.58Produces large amounts of green mana from a creature body and fits the same green ramp creature role. It is much stronger in most decks, but still serves as a mana engine on-board.
Karametra's Acolyteramp$0.31Taps for a large amount of green mana based on devotion, functioning as a creature-based mana engine. Like Gumato, it is a green creature that converts board presence into mana.
Viridian Joinerramp$0.35Another creature that taps to generate green mana, scaling with power rather than being a fixed source. It fills the same utility slot as a mana-producing green creature.
Circle of Dreams Druidramp$11.02A creature-based mana dork that can produce multiple green mana in token-heavy or wide boards. It is one of the closest functional upgrades to a large mana-producing creature.
Sanctum Weaverramp$4.74Taps for green mana equal to enchantment count, acting as a creature mana engine in the same vein. It is often more explosive than Gumato when built around.
Gaea's Touchramp$3.30Provides green mana acceleration in a mono-green shell, serving the same broad ramp purpose. While not a creature, it fills the role of a green mana source at a similar cost level.
Krosan Restorerramp$0.15A green creature that can generate extra mana, especially with threshold, making it a similar creature-based ramp piece. It is slower but can provide strong late-game mana bursts.
Overgrown Battlementramp$0.24Defensive green creature that turns board presence into mana, similar to a creature meant to accelerate you. It is cheaper and often easier to deploy early.