Activate Masked Meower by discarding a card and sacrificing it.
When Masked Meower dies, Luminous Broodmoth triggers, returning Masked Meower from your graveyard to the battlefield without a flying counter on it due to Solemnity.
Resolve the Masked Meower ability, causing you to draw a card.
Repeat.

Infinite self-discard triggers

Near-infinite creature ETB

Infinite draw triggers

Near-infinite creature LTB

Infinite rummaging

Near-infinite death triggers

Near-infinite creature sacrifice triggers

Solemnity

Luminous Broodmoth

Masked Meower

Cast Masked Meower by paying its mana cost.
Activate Masked Meower by sacrificing it.
When Masked Meower dies, Mortuary and Sifa Grent trigger.
Resolve the Mortuary trigger, putting Masked Meower from your graveyard onto the top of your library.
Resolve the Sifa Grent trigger, causing target opponent to lose 1 life and you to gain 1 life.
Cast Masked Meower from the top of your library by paying 1 life.
Repeat from step 2.

Near-infinite lifegain triggers

Near-infinite lifeloss

Near-infinite storm count

Mortuary

Bolas's Citadel

Sifa Grent

Activate Masked Meower by discarding  a card and sacrificing it.
When Masked Meower dies, Mikaeus triggers, returning Masked Meower from your graveyard to the battlefield with a +1/+1 counter on it.
Resolve the Masked Meower ability, causing you to draw a card.
Activate Masked Meower by discarding  a card and sacrificing it.
When Masked Meower dies, Luminous Broodmoth triggers, returning Masked Meower from your graveyard to the battlefield with a flying counter on it.
Resolve the Masked Meower ability, causing you to draw a card.
Repeat

Mikaeus, the Unhallowed

Activate Masked Meower by discarding a card and sacrificing it.
When Masked Meower dies, its persist ability triggers, returning it from your graveyard to the battlefield without a -1/-1 counter on it due to Vizier of Remedies.
Resolve the Masked Meower ability.
Repeat.

Eirdu, Carrier of Dawn // Isilu, Carrier of Twilight

Vizier of Remedies

Activate Masked Meower by discarding a card and sacrificing it.
When Masked Meower dies, Yedora triggers, returning Masked Meower from your graveyard to the battlefield face-down as a Forest land.
When Masked Meower enters the battlefield, Zimone triggers.
Holding priority, activate Masked Meower by tapping it, adding {G}.
Resolve the Zimone trigger, turning Masked Meower face-up.
Resolve the Masked Meower ability from step 1, causing you to draw a card.
Repeat.

Near-infinite landfall triggers

Near-infinite green mana

Zimone, Mystery Unraveler

Yedora, Grave Gardener

Activate Masked Meower by discarding a card and sacrificing it.
When Masked Meower dies, Ratadrabik triggers, creating a token copy of Masked Meower that is a 2/2 legendary Zombie in addition to its other types.
Resolve the Masked Meower ability.
Repeat using the Masked Meower token

Ratadrabik of Urborg

Leyline of Singularity

Activate a basic Swamp by tapping it, adding {B}.
Activate Kenrith's fifth ability by paying {B} due to Agatha, returning Masked Meower from your graveyard to the battlefield.
Activate Earthcraft by tapping Masked Meower, untapping the basic Swamp.
Activate Masked Meower by discarding a card and sacrificing it.
Repeat.

Kenrith, the Returned King

Earthcraft

Agatha of the Vile Cauldron

Combos with "Masked Meower"