Activate Relic of Legends by tapping Neerdiv, adding {U}.
Neerdiv triggers, causing a player to mill cards equal to its power.
Activate Freed from the Real by paying {U}, untapping Neerdiv.
Repeat.

Infinite mill

Infinite self-mill

Neerdiv, Devious Diver

Relic of Legends

Freed from the Real

Activate a creature using Fatestitcher's ability by tapping it, untapping Neerdiv.
Activate Neerdiv using Fatestitcher's ability by tapping it.
Neerdiv triggers, causing a player to mill cards equal to its power.
Resolve the Neerdiv ability from step 2, untapping another creature.
Repeat.

Agatha's Soul Cauldron

Fatestitcher

Activate Neerdiv using Aphetto Alchemist's ability by tapping it.
Neerdiv triggers, causing a player to mill cards equal to its power.
Resolve the Neerdiv ability from step 1, untapping it.
Repeat.

Combos with "Neerdiv, Devious Diver"