Peacekeeper

At the beginning of your upkeep, sacrifice this creature unless you pay {1}{W}.
Creatures can't attack.

Peace Talks

This turn and next turn, creatures can't attack, and players and permanents can't be the targets of spells or activated abilities.

Festival

Cast this spell only during an opponent's upkeep.
Creatures can't attack this turn.

Meekstone

Creatures with power 3 or greater don't untap during their controllers' untap steps.

Katabatic Winds

Phasing (This phases in or out before you untap during each of your untap steps. While it's phased out, it's treated as though it doesn't exist.)
Creatures with flying can't attack or block, and their activated abilities with {T} in their costs can't be activated.