Cast Storm Herd by paying {8}{W}{W}, creating a number of 1/1 Pegasus creature tokens equal to your life total.
When the Pegasi enter, Slash triggers that many times, dealing twice that much damage to each opponent.

Near-infinite creature ETB

Near-infinite creature tokens

Near-infinite damage

Storm Herd

Slash, Reptile Rampager

Draw a card.
The Locust God triggers, creating a 1/1 Insect creature token with flying and haste.
The Insect enters the battlefield, triggering Slash, dealing 2 damage to each opponent.
Curiosity triggers, causing you to draw a card.
Repeat from step 2.

Infinite card draw

Infinite draw triggers

Near-infinite creature tokens with haste

The Locust God

Curiosity

Draw a card.
The Locust God triggers, creating a 1/1 Insect creature token with flying and haste.
When the Insect enters the battlefield, Slash triggers, dealing 2 damage to each opponent.
Niv-Mizzet triggers, causing you to draw a card.
Repeat from step 2.

Niv-Mizzet, Visionary

Declare the creature with Breath of Fury attached and Slash as attackers.
Slash's second ability triggers, creating a creature token.
When the creature token enters, Slash's first ability triggers, dealing 2 damage to each opponent.
Deal combat damage using the creature that has Breath of Fury attached. 
Breath of Fury triggers, causing you to sacrifice the creature it is attached to, then attach Breath of Fury to the creature token, then causing you to untap all creatures you control and to get an additional combat phase after this one.
Repeat each combat phase.

Infinite creature ETB

Infinite creature LTB

Infinite combat damage

Infinite combat phases

Infinite damage

Infinite death triggers

Infinite mana creatures you control can produce

Infinite creature sacrifice triggers

Infinite untap of creatures you control

Breath of Fury

The Fire Crystal

Declare The Incredible Hulk and Slash as attackers.
Slash triggers, creating a creature token.
When the creature token enters, Slash triggers, dealing 2 damage to each opponent.
Holding priority, activate Goblin Bombardment by sacrificing a creature token, dealing 1 damage to The Incredible Hulk.
The Incredible Hulk triggers, putting a +1/+1 counter on it, then untapping it and causing you to get an additional combat phase after this one.
Repeat each combat phase.

Bruce Banner // The Incredible Hulk

Goblin Bombardment

Cause a creature to enter the battlefield under your control.
Slash triggers, dealing 2 damage to each opponent.
The Red Terror triggers, putting a +1/+1 counter on itself.
Animation Module triggers, causing you to pay {1} to create a 1/1 Servo artifact creature token.
When the Servo enters, Slash triggers.
Holding priority, activate Phyrexian Altar by sacrificing the Servo, adding {1}.
Resolve the Slash triggers, dealing 2 damage to each opponent.
Repeat from step 3.

Infinite +1/+1 counters on a creature

The Red Terror

Animation Module

Phyrexian Altar

Combos with "Slash, Reptile Rampager"