The most famous example is the easy infinite Zirda has with either Basalt Monolith or Grim Monolith untapping a Monolith isnt a mana ability, it just happens to control how often we can use the attached mana ability
Vivillon disrupts opponents by reshuffling their hands, while Decidueye ex takes advantage of that disruption to deliver high-damage attacks without energy cost under specific conditions
We can think of it kind of like a Venn Diagram in a box
Matzalantli, the Great Door / The Core Matzalantli, the Great Door is a reworked version of Azor's Gateway, with an arguably better front side and a comparable back half with The Core still tapping for obscene amounts of mana
Grateful Apparition Grateful Apparition is a strictly better Thrummingbird save for color, giving you the same cascading advantage but also triggering on damage to a planeswalker
Its got an agreeable casting cost-to-damage ratio with five mana for five damage, a full two mana better than Starstorm for five damage would be