Activate Phyrexian Altar by sacrificing Monastery Flock, adding {U}.
When Monastery Flock dies, Missy's first ability triggers, returning Monastery Flock from your graveyard to the battlefield face down as a 2/2 Cyberman artifact creature.
Activate Monastery Flock's morph ability by paying {U}, turning it face up.
Repeat.

Infinite death triggers

Infinite ETB

Infinite LTB

Infinite sacrifice triggers

Missy

Phyrexian Altar

Monastery Flock

Activate Phyrexian Altar by sacrificing Monastery Flock, adding {U}.
When Monastery Flock dies, Yedora triggers, returning Monastery Flock from your graveyard to the battlefield face down as a Forest land.
Activate Monastery Flock by tapping it, adding {G}.
Activate Monastery Flock's morph ability by paying {U}, turning it face up.
Repeat.

Infinite green mana

Infinite landfall triggers

Yedora, Grave Gardener

Combos with "Monastery Flock"