Kenrith, the Returned King, Relic of Legends, Agatha of the Vile Cauldron, and Sidisi, Undead Vizier

Prerequisites

• Kenrith, the Returned King on the battlefield
• Relic of Legends on the battlefield
• Agatha of the Vile Cauldron on the battlefield
• Sidisi, Undead Vizier in the graveyard
• available

Steps

1. Activate Kenrith's fifth ability by paying due to Agatha, returning Sidisi from your graveyard to the battlefield
2. When Sidisi enters, its exploit ability triggers
3. Holding priority, activate Relic of Legends' second ability by tapping Sidisi, adding
4. Resolve the Sidisi trigger, causing you to sacrifice it
5. Sidisi's second ability triggers, causing you to search your library for a card and put it into your hand
6. Repeat

Results

• Infinite ETB
• Infinite LTB
• Infinite card draw
• Infinite death triggers
• Infinite sacrifice triggers