Activate Wall of Limbs by using Walking Ballista's ability by removing a +1/+1 counter from it, dealing 1 damage to any target and causing you to gain 1 life due to its lifelink.
Wall of Limbs triggers, putting a +1/+1 counter on it.
Repeat.

Infinite damage

Infinite lifegain triggers

Infinite lifegain

Agatha's Soul Cauldron

Walking Ballista

Wall of Limbs

Activate Wall of Limbs using Spike Feeder's second ability by removing a +1/+1 counter from it, causing you to gain 2 life.
Wall of Limbs triggers, putting a +1/+1 counter on it.
Repeat.

Spike Feeder

Cause a creature to enter the battlefield under your control.
Ajani's Welcome triggers, causing you to gain 1 life.
Wall of Limbs 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.
The Servo enters the battlefield, triggering Ajani's Welcome.
Holding priority, activate Ashnod's Altar by sacrificing the Servo, adding {C}{C}.
Resolve the Ajani's Welcome trigger, causing you to gain 1 life.
Repeat from step 3.

Infinite +1/+1 counters on a creature

Infinite colorless mana

Infinite creature tokens

Infinite death triggers

Infinite ETB

Infinite LTB

Infinite sacrifice triggers

Animation Module

Ajani's Welcome

Ashnod's Altar

Combos with "Wall of Limbs"