Welcome Party GRU
Enchantment
Whenever a creature enters the battlefield, it gains haste until end of turn and must attack if able that turn. All creatures able to block that creature must do so that turn.
Farewell Party BGR
Enchantment
Whenever a creature leaves the battlefield, all other creatures become tapped.
Welcome Back Party WBG
Enchantment
Whenever a creature is put into the graveyard from the battlefield, its controller puts a sorrow counter on all creatures he controls.
Whenever a creature is returned from a graveyard to the battlefield, its controller removes all sorrow counters from each creature he controls and places X +1/+1 counters on each creature, where X is the number of sorrow counters removed from that creature.