Agatha's Soul Cauldron, Famished Paladin, and Soulmender

Prerequisites

• Agatha's Soul Cauldron on the battlefield
• Famished Paladin on the battlefield
• Soulmender in exile
• Famished Paladin has at least one +1/+1 counter on it and does not have summoning sickness

Steps

1. Activate Famished Paladin using Soulmender's ability by tapping it, causing you to gain 1 life
2. Famished Paladin triggers, untapping itself
3. Repeat

Results

• Infinite lifegain
• Infinite lifegain triggers