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.

Infinite lifegain

Infinite lifegain triggers

Agatha's Soul Cauldron

Spike Feeder

Wall of Limbs

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 Wall of Limbs

Infinite colorless mana

Infinite creature tokens

Infinite death triggers

Infinite ETB

Infinite LTB

Infinite sacrifice triggers

Animation Module

Ajani's Welcome

Ashnod's Altar

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

Walking Ballista

Combos with "Wall of Limbs"