Agatha of the Vile Cauldron + Magus of the Candelabra + Umbral Mantle
Agatha of the Vile Cauldron
Magus of the Candelabra
Umbral Mantle
Infinite power and toughness for most creatures you control until end of turnInfinite mana lands you control can produceInfinite untap of creatures you controlInfinite mana creatures you control can produceInfinitely large creature until end of turnInfinite untap of lands you control
How it works
Activate up to three lands by tapping them, adding at least 3.
Activate Magus of the Candelabra by tapping it and paying 1 due to Agatha of the Vile Cauldron, untapping the five lands.
Activate Magus of the Candelabra by paying 1 due to Agatha of the Vile Cauldron and untapping it, giving itself +2/+2 until end of turn.
Repeat.
Once you have infinite mana, if you have infinite and , you may use it to activate Agatha of the Vile Cauldron's ability.
This clever loop turns Magus of the Candelabra into a one-man mana engine by leveraging Umbral Mantle to repeatedly untap it while generating a surplus of mana. Agatha of the Vile Cauldron is the linchpin of the strategy, as her passive ability drastically discounts the untap cost of Umbral Mantle down to just {1} mana. Because Magus of the Candelabra can untap lands to generate more mana than this reduced activation cost requires, you can cycle the process infinitely to generate arbitrary amounts of mana and pump Magus of the Candelabra to astronomical proportions.