Windborn Muse

Flying
Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Ghostly Prison

Creatures can't attack you unless their controller pays {2} for each creature they control that's attacking you.

Gwafa Hazid, Profiteer

{W}{U}, {T}: Put a bribery counter on target creature you don't control. Its controller draws a card.
Creatures with bribery counters on them can't attack or block.

Grand Arbiter Augustin IV

White spells you cast cost {1} less to cast.
Blue spells you cast cost {1} less to cast.
Spells your opponents cast cost {1} more to cast.

Azorius Chancery

Azorius Chancery enters tapped.
When Azorius Chancery enters, return a land you control to its owner's hand.
{T}: Add {W}{U}.

Geist of Saint Traft

Hexproof (This creature can't be the target of spells or abilities your opponents control.)
Whenever Geist of Saint Traft attacks, create a 4/4 white Angel creature token with flying that's tapped and attacking. Exile that token at end of combat.

Propaganda

Mirror-Sigil Sergeant

Trample
At the beginning of your upkeep, if you control a blue permanent, you may create a token that's a copy of Mirror-Sigil Sergeant.