Negate

Aggravated Assault

{3}{R}{R}: Untap all creatures you control. After this main phase, there is an additional combat phase followed by an additional main phase. Activate only as a sorcery.

Arm with Aether

Until end of turn, creatures you control gain "Whenever this creature deals damage to an opponent, you may return target creature that player controls to its owner's hand."

Thrill of Possibility

As an additional cost to cast this spell, discard a card.
Draw two cards.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Yasova Dragonclaw

Trample
At the beginning of combat on your turn, you may pay {1}{U/R}{U/R}. If you do, gain control of target creature an opponent controls with power less than Yasova Dragonclaw's power until end of turn, untap that creature, and it gains haste until end of turn.

Aggressive Mammoth

Trample (This creature can deal excess combat damage to the player or planeswalker it's attacking.)
Other creatures you control have trample.

Atarka's Command

Choose two —
• Your opponents can't gain life this turn.
• Atarka's Command deals 3 damage to each opponent.
• You may put a land card from your hand onto the battlefield.
• Creatures you control get +1/+1 and gain reach until end of turn.

Chaos Warp

The owner of target permanent shuffles it into their library, then reveals the top card of their library. If it's a permanent card, they put it onto the battlefield.

Explore

You may play an additional land this turn.
Draw a card.

Archetype of Imagination

Creatures you control have flying.
Creatures your opponents control lose flying and can't have or gain flying.

Sol Ring

Beguiler of Wills

{T}: Gain control of target creature with power less than or equal to the number of creatures you control.

Akki Battle Squad

Whenever one or more modified creatures you control attack, untap all modified creatures you control. After this phase, there is an additional combat phase. This ability triggers only once each turn. (Equipment, Auras you control, and counters are modifications.)

Cultivate

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Beastmaster Ascension

Whenever a creature you control attacks, you may put a quest counter on this enchantment.
As long as this enchantment has seven or more quest counters on it, creatures you control get +5/+5.

Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Preordain

Scry 2, then draw a card. (To scry 2, look at the top two cards of your library, then put any number of them on the bottom and the rest on top in any order.)

Balmor, Battlemage Captain

Flying
Whenever you cast an instant or sorcery spell, creatures you control get +1/+0 and gain trample until end of turn.

Swiftfoot Boots

Equipped creature has hexproof and haste. (It can't be the target of spells or abilities your opponents control. It can attack and {T} no matter when it came under your control.)
Equip {1} ({1}: Attach to target creature you control. Equip only as a sorcery.)

Arni Slays the Troll

(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.)
I — Target creature you control fights up to one target creature you don't control.
II — Add {R}. Put two +1/+1 counters on up to one target creature you control.
III — You gain life equal to the greatest power among creatures you control.

Archetype of Aggression

Creatures you control have trample.
Creatures your opponents control lose trample and can't have or gain trample.

Berserkers' Onslaught

Attacking creatures you control have double strike.

Stolen Strategy

At the beginning of your upkeep, exile the top card of each opponent's library. Until end of turn, you may cast spells from among those exiled cards, and you may spend mana as though it were mana of any color to cast those spells.

Archetype of Endurance

Creatures you control have hexproof.
Creatures your opponents control lose hexproof and can't have or gain hexproof.