Vedalken Orrery

You may cast spells as though they had flash.

Yeva, Nature's Herald

Flash (You may cast this spell any time you could cast an instant.)
You may cast green creature spells as though they had flash.

Emergence Zone

{T}: Add {C}.
{1}, {T}, Sacrifice Emergence Zone: You may cast spells this turn as though they had flash.

Mountain

Forest

Plains

Winding Canyons

{T}: Add {C}.
{2}, {T}: You may cast creature spells this turn as though they had flash.

Vivien, Champion of the Wilds

You may cast creature spells as though they had flash.
+1: Until your next turn, up to one target creature gains vigilance and reach.
−2: Look at the top three cards of your library. Exile one face down and put the rest on the bottom of your library in any order. For as long as it remains exiled, you may cast it if it's a creature spell.

Vernal Equinox

Any player may cast creature and enchantment spells as though they had flash.

Marisi, Breaker of the Coil

Your opponents can't cast spells during combat.
Whenever a creature you control deals combat damage to a player, goad each creature that player controls. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)