Standard Bearer

While an opponent is choosing targets as part of casting a spell they control or activating an ability they control, that player must choose at least one Flagbearer on the battlefield if able.

Novice Inspector

When Novice Inspector enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this artifact: Draw a card.")

Recommission

Return target artifact or creature card with mana value 3 or less from your graveyard to the battlefield. If a creature enters this way, it enters with an additional +1/+1 counter on it.

Swamp

Corrupted Conviction

As an additional cost to cast this spell, sacrifice a creature.
Draw two cards.

Children of Korlis

Sacrifice Children of Korlis: You gain life equal to the life you've lost this turn. (Damage causes loss of life.)

Midnight Scavengers

When Midnight Scavengers enters, you may return target creature card with mana value 3 or less from your graveyard to your hand.
(Melds with Graf Rats.)

Benalish Sleeper

Kicker {B} (You may pay an additional {B} as you cast this spell.)
When Benalish Sleeper enters, if it was kicked, each player sacrifices a creature of their choice.

Graf Rats

At the beginning of combat on your turn, if you both own and control Graf Rats and a creature named Midnight Scavengers, exile them, then meld them into Chittering Host.

Plains

Dash Hopes

When you cast this spell, any player may pay 5 life. If a player does, counter Dash Hopes.
Counter target spell.

Boros Elite

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