Phalanx Tactics

Target creature you control gets +2/+1 until end of turn. Each other creature you control gets +1/+1 until end of turn.

Hero of the Winds

Flying
Whenever you cast a spell that targets Hero of the Winds, creatures you control get +1/+0 until end of turn.

Thriving Heath

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

Enchant creature
Enchanted creature gets +2/+2, has first strike, and is a Knight in addition to its other types. (It deals combat damage before creatures without first strike.)

Defiant Strike

Target creature gets +1/+0 until end of turn.
Draw a card.

Hero of the Pride

Whenever you cast a spell that targets Hero of the Pride, creatures you control get +1/+0 until end of turn.

Plains

Feat of Resistance

Put a +1/+1 counter on target creature you control. It gains protection from the color of your choice until end of turn. (It can't be blocked, targeted, dealt damage, enchanted, or equipped by anything of that color.)

Siege Striker

Double strike (This creature deals both first-strike and regular combat damage.)
Whenever Siege Striker attacks, you may tap any number of untapped creatures you control. Siege Striker gets +1/+1 until end of turn for each creature tapped this way.

Valorous Stance

Choose one —
• Target creature gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)
• Destroy target creature with toughness 4 or greater.

Daybreak Charger

When Daybreak Charger enters, target creature gets +2/+0 until end of turn.

Mavinda, Students' Advocate

Flying
{0}: You may cast target instant or sorcery card from your graveyard this turn. If that spell doesn't target a creature you control, it costs {8} more to cast this way. If that spell would be put into your graveyard, exile it instead. Activate only once each turn. (You still pay the spell's costs. Timing rules for the spell still apply.)