Emrakul, the Exigent Doom

Mono Green can plausibly reach ten mana; unlike Valgavoth, it lacks disruption, but its cast-triggered untap and ward make it a potent top-end payoff.

Could be wrong if Landfall may be too board-focused or fast to spend slots on a ten-mana finisher, and the hand-exile mode repays its setup slowly.

Lotus Field can cast it and exploit the untap trigger, but Zacama offers a cheaper untap payoff with immediate board control; this is likely a niche finisher.

Could be wrong if A dedicated big-mana shell could value the post-cast mana highly enough to make it a recurring one- or two-copy payoff.

Colorless ramp can test it as a protected two-hit clock that leaves mana open on cast, but Ulamog's immediate exile trigger is generally the more reliable payoff.

Could be wrong if If the untap trigger enables a compelling post-cast sequence, it could displace more established ten-mana threats rather than remain a supplement.

Cloudpost can cast it, and untapping its lands is meaningful, but Ulamog answers key permanents immediately while Karakas makes this legendary threat unreliable.

Could be wrong if Cloudpost's mana output may make the retained mana and ward sufficiently valuable to offset its lack of an immediate removal trigger.

A strong colorless-ramp finisher: reaching ten leaves mana available after casting, and flying, trample, and ward make it difficult to race or remove.

Could be wrong if Ten mana and no immediate removal or card advantage may leave it behind established Eldrazi finishers in optimized multiplayer lists.

A cast 12/12 flying trampler with ward will usually end the game quickly; its hand ability helps reach ten, though it costs a meaningful development turn.

Could be wrong if Unknown speed, fixing, and removal may make ten mana too slow or make the setup ability too costly in actual drafts.