Tameshi, Reality Architect + Mind Over Matter + Ancient Den + Darksteel Citadel

Tameshi, Reality Architect
Mind Over Matter
Ancient Den
Darksteel Citadel

Requires
Darksteel Citadel in hand. All other permanents on the battlefield.
Steps
  1. Activate Ancient Den by tapping it, adding w
  2. Activate Mind over Matter by discarding Darksteel Citadel, untapping Ancient Den
  3. Activate Ancient Den by tapping it, adding w
  4. Activate Tameshi by paying w and returning Ancient Den from the battlefield to your hand, returning Darksteel Citadel from your graveyard to the battlefield
  5. Activate Mind over Matter by discarding Ancient Den, untapping any applicable permanent
  6. Activate Tameshi by paying w and returning Darksteel Citadel from the battlefield to your hand, returning Ancient Den from your graveyard to the battlefield
  7. Repeat
Results
Infinite mana permanents you control can produce. Infinite landfall triggers. Infinite self-discard triggers. Infinite untap of permanents you control.