Millstone

The Millennium Calendar

Whenever you untap one or more permanents during your untap step, put that many time counters on The Millennium Calendar.
{2}, {T}: Double the number of time counters on The Millennium Calendar.
When there are 1,000 or more time counters on The Millennium Calendar, sacrifice it and each opponent loses 1,000 life.

Unwinding Clock

Untap all artifacts you control during each other player's untap step.

Volrath's Stronghold

{T}: Add {C}.
{1}{B}, {T}: Put target creature card from your graveyard on top of your library.

All Will Be One

Whenever you put one or more counters on a permanent or player, All Will Be One deals that much damage to target opponent, creature an opponent controls, or planeswalker an opponent controls.