Activate Vizier of Tumbling Sands by tapping it, targeting Second Wind.
Vizier of Tumbling Sands triggers, causing you to loot.
Resolve the Vizier of Tumbling Sands ability, untapping Second Wind.
Activate Second Wind's second ability by tapping it, untapping Vizier of Tumbling Sands.
Repeat.

Infinite draw triggers

Infinite looting

Infinite self-discard triggers

Unctus, Grand Metatect

Second Wind

Vizier of Tumbling Sands

Activate Kelpie Guide's first ability by tapping it, targeting Second Wind.
Kelpie Guide triggers, causing you to loot.
Resolve the Kelpie Guide ability, untapping Second Wind.
Activate Second Wind's second ability by tapping it, untapping Kelpie Guide.
Repeat.

Kelpie Guide

Activate Clever Conjurer by tapping it, targeting Second Wind.
Clever Conjurer triggers, causing you to loot.
Resolve the Clever Conjurer ability, untapping Second Wind.
Activate Second Wind's second ability by tapping it, untapping Clever Conjurer.
Repeat.

Clever Conjurer

Activate the mana-producing creature by tapping it, adding at least {2}.
Activate Yenna by paying {2} and tapping it, creating a token copy of Estrid's Invocation. Choose to have Estrid's Invocation enter the battlefield as a copy of Second Wind attached to the mana-producing creature. Then, untap Yenna and scry 2.
Activate the Second Wind token's second ability by tapping it, untapping the mana-producing creature.
Repeat.

Infinite scry 2

Creature that taps for 2+ mana

Yenna, Redtooth Regent

Estrid's Invocation

Activate the mana-producing creature by tapping it, adding at least {2}.
Activate Yenna by paying {2} and tapping it, creating a token copy of Second Wind attached to the mana-producing creature, then untapping Yenna and causing you to scry 2.
Activate the Second Wind token's second ability by tapping it, untapping the mana-producing creature.
Activate Thaumatog by sacrificing the Second Wind token.
Repeat.

Infinitely large Thaumatog until end of turn

Thaumatog

Activate Goblin Welder by tapping it, sacrificing Second Wind and returning Tezzeret the Seeker from your graveyard to the battlefield.
Activate Tezzeret the Seeker's first ability by putting a loyalty counter on them, untapping Goblin Welder and any other nonland permanent.
Activate Goblin Welder by tapping it, sacrificing Tezzeret the Seeker and returning Second Wind from your graveyard to the battlefield attached to Goblin Welder.
Activate Second Wind's last ability by tapping it, untapping Goblin Welder.
Repeat.

Infinite untap of nonland permanents

Encroaching Mycosynth

Goblin Welder

Tezzeret the Seeker

Activate the mana-producing creature by tapping it, adding at least {2}.
Activate Yenna by paying {2} and tapping it, creating a token copy of Second Wind attached to the mana-producing creature, then untapping Yenna and causing you to scry 2.
Put the oldest Second Wind into your graveyard due to the legend rule.
Activate the Second Wind token's second ability by tapping it, untapping the mana-producing creature.
Repeat.

Combos with "Second Wind"