Space-Time Anomaly

Target player mills cards equal to your life total.

Riverchurn Monument

{1}, {T}: Any number of target players each mill two cards. (Each of them puts the top two cards of their library into their graveyard.)
Exhaust — {2}{U}{U}, {T}: Any number of target players each mill cards equal to the number of cards in their graveyard. (Activate each exhaust ability only once.)

Hope Estheim

Lifelink
At the beginning of your end step, each opponent mills X cards, where X is the amount of life you gained this turn.

Fumigate

Destroy all creatures. You gain 1 life for each creature destroyed this way.