Gideon's Avenger

Whenever a creature an opponent controls becomes tapped, put a +1/+1 counter on this creature.

Reveille Squad

Whenever one or more creatures attack you, if this creature is untapped, you may untap all creatures you control.

Combat Calligrapher

Flying
Inklings can't attack you or planeswalkers you control.
Whenever a player attacks one of your opponents, that attacking player creates a tapped 2/1 white and black Inkling creature token with flying that's attacking that opponent.

Kitt Kanto, Mayhem Diva

When Kitt Kanto enters, create a 1/1 green and white Citizen creature token.
At the beginning of combat on each player's turn, you may tap two untapped creatures you control. When you do, target creature that player controls gets +2/+2 and gains trample until end of turn. Goad that creature.

Veteran of the Depths

Whenever this creature becomes tapped, you may put a +1/+1 counter on it.

Tahngarth, First Mate

Tahngarth can't be blocked by more than one creature.
Whenever an opponent attacks with one or more creatures, if Tahngarth is tapped, you may have that opponent gain control of Tahngarth until end of combat. If you do, choose a player or planeswalker that opponent is attacking. Tahngarth is attacking that player or planeswalker.

Renegade Wheelsmith

Whenever this creature becomes tapped, target creature can't block this turn.

Emmara, Soul of the Accord

Whenever Emmara becomes tapped, create a 1/1 white Soldier creature token with lifelink.

Scaretiller

Whenever this creature becomes tapped, choose one —
• You may put a land card from your hand onto the battlefield tapped.
• Return target land card from your graveyard to the battlefield tapped.

Radha, Coalition Warlord

Domain — Whenever Radha becomes tapped, another target creature you control gets +X/+X until end of turn, where X is the number of basic land types among lands you control.

Warchanter Skald

Whenever this creature becomes tapped, if it's enchanted or equipped, create a 2/1 red Dwarf Berserker creature token.