Arashin Foremost

Double strike
Whenever this creature enters or attacks, another target Warrior creature you control gains double strike until end of turn.

Wraith, Vicious Vigilante

Double strike
Fear Gas — Wraith can't be blocked.

Sensational Spider-Man

Whenever Sensational Spider-Man attacks, tap target creature defending player controls and put a stun counter on it. Then you may remove up to three stun counters from among all permanents. Draw cards equal to the number of stun counters removed this way.

Avenging Huntbonder

Double strike
Whenever this creature attacks, put a double strike counter on another target attacking creature.

The Wandering Rescuer

Flash
Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Double strike
Other tapped creatures you control have hexproof.

Spider-UK

Web-slinging {2}{W} (You may cast this spell for {2}{W} if you also return a tapped creature you control to its owner's hand.)
At the beginning of your end step, if two or more creatures entered the battlefield under your control this turn, you draw a card and gain 2 life.

Odric, Lunarch Marshal

At the beginning of each combat, creatures you control gain first strike until end of turn if a creature you control has first strike. The same is true for flying, deathtouch, double strike, haste, hexproof, indestructible, lifelink, menace, reach, skulk, trample, and vigilance.

Errant, Street Artist

Flash
Defender, haste
{1}{U}, {T}: Copy target spell you control that wasn't cast. You may choose new targets for the copy.

Katara, Waterbending Master

Whenever you cast a spell during an opponent's turn, you get an experience counter.
Whenever Katara attacks, you may draw a card for each experience counter you have. If you do, discard a card.

Dromoka Captain

First strike
Whenever this creature attacks, bolster 1. (Choose a creature with the least toughness among creatures you control and put a +1/+1 counter on it.)

Elite Scaleguard

When this creature enters, bolster 2. (Choose a creature with the least toughness among creatures you control and put two +1/+1 counters on it.)
Whenever a creature you control with a +1/+1 counter on it attacks, tap target creature defending player controls.

Goldbug, Scrappy Scout

Living metal (During your turn, this Vehicle is also a creature.)
Human spells you control can't be countered.
Whenever Goldbug and at least one Human attack, draw a card and convert Goldbug.

Goldbug, Humanity's Ally

More Than Meets the Eye {W}{U} (You may cast this card converted for {W}{U}.)
Prevent all combat damage that would be dealt to attacking Humans you control.
Whenever you cast your second spell each turn, convert Goldbug.