Indomitable Will

Flash (You may cast this spell any time you could cast an instant.)
Enchant creature
Enchanted creature gets +1/+2.

Arena Trickster

Whenever you cast your first spell during each opponent's turn, put a +1/+1 counter on Arena Trickster.

Infuriate

Target creature gets +3/+2 until end of turn.

Aspect of Manticore

Flash
Enchant creature
When Aspect of Manticore enters, enchanted creature gains first strike until end of turn.
Enchanted creature gets +2/+0.

Hero of the Pride

Whenever you cast a spell that targets Hero of the Pride, creatures you control get +1/+0 until end of turn.

Hero of the Games

Whenever you cast a spell that targets Hero of the Games, creatures you control get +1/+0 until end of turn.

Mountain

Boros Garrison

Boros Garrison enters tapped.
When Boros Garrison enters, return a land you control to its owner's hand.
{T}: Add {R}{W}.

Wind-Scarred Crag

This land enters tapped.
When this land enters, you gain 1 life.
{T}: Add {R} or {W}.

Boros Guildgate

This land enters tapped.
{T}: Add {R} or {W}.

Plains

Sentinel's Eyes

Enchant creature
Enchanted creature gets +1/+1 and has vigilance.
Escape—{W}, Exile two other cards from your graveyard. (You may cast this card from your graveyard for its escape cost.)

Transcendent Envoy

Flying
Aura spells you cast cost {1} less to cast.

Gateway Plaza

Gateway Plaza enters tapped.
When Gateway Plaza enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Karametra's Blessing

Target creature gets +2/+2 until end of turn. If it's an enchanted creature or enchantment creature, it also gains hexproof and indestructible until end of turn. (It can't be the target of spells or abilities your opponents control. Damage and effects that say "destroy" don't destroy it.)