Plains

Jousting Lance

Equipped creature gets +2/+0.
During your turn, equipped creature has first strike.
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Éowyn, Lady of Rohan

At the beginning of combat on your turn, target creature gains your choice of first strike or vigilance until end of turn. If that creature is equipped, it gains first strike and vigilance until end of turn instead.
Equip abilities you activate cost {1} less to activate.

Kwende, Pride of Femeref

Double strike
Creatures you control with first strike have double strike.

Angelic Destiny

Enchant creature
Enchanted creature gets +4/+4, has flying and first strike, and is an Angel in addition to its other types.
When enchanted creature dies, return this card to its owner's hand.

Viridian Claw

Equipped creature gets +1/+0 and has first strike.
Equip {1}

Knighthood

Archetype of Courage

Creatures you control have first strike.
Creatures your opponents control lose first strike and can't have or gain first strike.

Advance Scout

First strike
{W}: Target creature gains first strike until end of turn.

Maul of the Skyclaves

When this Equipment enters, attach it to target creature you control.
Equipped creature gets +2/+2 and has flying and first strike.(It deals combat damage before creatures without first strike.)
Equip {2}{W}{W}

Cartouche of Solidarity

Enchant creature you control
When this Aura enters, create a 1/1 white Warrior creature token with vigilance.
Enchanted creature gets +1/+1 and has first strike. (It deals combat damage before creatures without first strike.)

Sharpened Pitchfork

Equipped creature has first strike.
As long as equipped creature is a Human, it gets +1/+1.
Equip {1}

Hyena Umbra

Enchant creature
Enchanted creature gets +1/+1 and has first strike.
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Power Matrix

{T}: Target creature gets +1/+1 and gains flying, first strike, and trample until end of turn.

Lashknife

If you control a Plains, you may tap an untapped creature you control rather than pay this spell's mana cost.
Enchant creature
Enchanted creature has first strike.