Ordruun Mentor

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever you attack a player, target creature that's attacking that player gains first strike until end of turn.

Roc Charger

Flying
Whenever this creature attacks, target attacking creature without flying gains flying until end of turn.

Boros Garrison

This land enters tapped.
When this land enters, return a land you control to its owner's hand.
{T}: Add {R}{W}.

Thriving Heath

This land enters tapped. As it enters, choose a color other than white.
{T}: Add {W} or one mana of the chosen color.

Parhelion Patrol

Flying
Vigilance (Attacking doesn't cause this creature to tap.)
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)

Plains

Martial Impetus

Enchant creature
Enchanted creature gets +1/+1 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, each other creature that's attacking one of your opponents gets +1/+1 until end of turn.

Boros Signet

Intervention

Intervention deals 3 damage to any target and you gain 3 life.

Integrity

Target creature gets +2/+2 until end of turn.

Integrity // Intervention

Fresh-Faced Recruit

During your turn, this creature has first strike.

Mighty Leap

Target creature gets +2/+2 and gains flying until end of turn.

Novice Inspector

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

Boros Guildgate

This land enters tapped.
{T}: Add {R} or {W}.

Sunhome Stalwart

First strike (This creature deals combat damage before creatures without first strike.)
Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)

Finale of Glory

Create X 2/2 white Soldier creature tokens with vigilance. If X is 10 or more, also create X 4/4 white Angel creature tokens with flying and vigilance.

Aegis of the Legion

Equipped creature gets +1/+1 and has mentor. (Whenever it attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever equipped creature mentors a creature, put a shield counter on that creature. (If that creature would be dealt damage or destroyed, remove a shield counter from it instead.)
Equip {3}