Isshin, Two Heavens as One

If a creature attacking causes a triggered ability of a permanent you control to trigger, that ability triggers an additional time.

Cave People

Whenever Cave People attacks, it gets +1/-2 until end of turn.
{1}{R}{R}, {T}: Target creature gains mountainwalk until end of turn. (It can't be blocked as long as defending player controls a Mountain.)

Warmind Infantry

Battalion — Whenever Warmind Infantry and at least two other creatures attack, Warmind Infantry gets +2/+0 until end of turn.

Flanking Troops

Whenever Flanking Troops attacks, you may tap target creature.

Keldon Berserker

Whenever Keldon Berserker attacks, if you control no untapped lands, it gets +3/+0 until end of turn.

Lurking Nightstalker

Whenever Lurking Nightstalker attacks, it gets +2/+0 until end of turn.

Flowstone Charger

Whenever Flowstone Charger attacks, it gets +3/-3 until end of turn.

Boros Elite

Battalion — Whenever Boros Elite and at least two other creatures attack, Boros Elite gets +2/+2 until end of turn.

Firemane Avenger

Flying
Battalion — Whenever Firemane Avenger and at least two other creatures attack, Firemane Avenger deals 3 damage to any target and you gain 3 life.

Vicious Kavu

Whenever Vicious Kavu attacks, it gets +2/+0 until end of turn.

Ravenous Skirge

Flying
Whenever Ravenous Skirge attacks, it gets +2/+0 until end of turn.

Tajic, Blade of the Legion

Indestructible
Battalion — Whenever Tajic, Blade of the Legion and at least two other creatures attack, Tajic gets +5/+5 until end of turn.

Wei Ambush Force

Whenever Wei Ambush Force attacks, it gets +2/+0 until end of turn.

Cho-Arrim Bruiser

Whenever Cho-Arrim Bruiser attacks, you may tap up to two target creatures.

Nav Squad Commandos

Battalion — Whenever Nav Squad Commandos and at least two other creatures attack, Nav Squad Commandos gets +1/+1 until end of turn. Untap it.

Makeshift Battalion

Battalion — Whenever Makeshift Battalion and at least two other creatures attack, put a +1/+1 counter on Makeshift Battalion.

Loafing Giant

Whenever Loafing Giant attacks or blocks, mill a card. If a land card was milled this way, prevent all combat damage Loafing Giant would deal this turn.