Solemn Recruit

Mana cost: {1}{W}{W}
Type: Creature — Dwarf Warrior
Power / toughness: 2 / 2
Set: Aether Revolt #22 (rare)
Price: $0.17 USD

Double strike
Revolt — At the beginning of your end step, if a permanent left the battlefield under your control this turn, put a +1/+1 counter on this creature.

Solemn Recruit has 4 printings, first in Aether Revolt (2017). EDHREC ranks it #16,248 among Commander cards. It appears most in Nalia de'Arnise decks (962 on EDHREC). 2 public decks on TCG run it. It has 5 official rulings.

Legality

commander: legal
legacy: legal
vintage: legal
pauper: not legal
modern: legal
pioneer: legal
standard: not legal
brawl: not legal

Public decks that run Solemn Recruit

Party Time - Commander Legends: Battle for Baldur's Gate, led by Nalia de'Arnise
Symbiotic Swarm - Commander 2020, led by Kathril, Aspect Warper

Commanders that run Solemn Recruit most

Deck counts from EDHREC.

Often played with Solemn Recruit

Cards that show up in the same decks on EDHREC.

Rulings

2017-02-09: Tokens that leave the battlefield will satisfy a revolt ability.
2017-02-09: All cards in the Aether Revolt set with triggered revolt abilities use an intervening "if" clause. A permanent you controlled must have left the battlefield earlier in the turn in order for these abilities to trigger; otherwise they do nothing. In other words, there's no way to have the ability trigger if no permanent you controlled has left the battlefield that turn, even if you intend to have one do so in response to the triggered ability.
2017-02-09: Revolt abilities don't care why the permanent left the battlefield, who caused it to move, or where it moved to. They're equally satisfied by an artifact you sacrificed to pay a cost, a creature you controlled that was destroyed by Murder, or an enchantment you returned to your hand with Leave in the Dust.
2017-02-09: Revolt abilities check only whether a permanent you controlled left the battlefield this turn or not. They don't apply multiple times if more than one permanent you controlled left the battlefield. They don't check whether the permanent that left the battlefield is still in the zone it moved to.
2017-02-09: Energy counters aren't permanents. Paying {E} won't satisfy a revolt ability.