Lightning Bolt

Lightning Bolt deals 3 damage to any target.

Rowan, Fearless Sparkmage

+1: Up to one target creature gets +3/+0 and gains first strike until end of turn.
−2: Rowan deals 1 damage to each of up to two target creatures. Those creatures can't block this turn.
−9: Gain control of all creatures until end of turn. Untap them. They gain haste until end of turn.

Syr Carah, the Bold

Whenever Syr Carah or an instant or sorcery spell you control deals damage to a player, exile the top card of your library. You may play that card this turn.
{T}: Syr Carah deals 1 damage to any target.

Dizzying Swoop

Tap up to two target creatures. (Then exile this card. You may cast the creature later from exile.)

Ardenvale Tactician

Ardenvale Tactician // Dizzying Swoop

Mountain

Brimstone Trebuchet

Defender, reach
{T}: This creature deals 1 damage to each opponent.
Whenever a Knight you control enters, untap this creature.

Plains

Youthful Knight

Ogre Errant

Whenever this creature attacks, another target attacking Knight gains menace until end of turn. (It can't be blocked except by two or more creatures.)

Garrison Griffin

Flying
Whenever this creature attacks, target Knight you control gains flying until end of turn.

Joust

Choose target creature you control and target creature you don't control. The creature you control gets +2/+1 until end of turn if it's a Knight. Then those creatures fight each other. (Each deals damage equal to its power to the other.)

Acclaimed Contender

When this creature enters, if you control another Knight, look at the top five cards of your library. You may reveal a Knight, Aura, Equipment, or legendary artifact card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.

Rowan's Stalwarts

When this creature enters, you may search your library and/or graveyard for a card named Rowan, Fearless Sparkmage, reveal it, and put it into your hand. If you search your library this way, shuffle.

Boulder Rush

Target creature gets +2/+0 until end of turn. (Then exile this card. You may cast the creature later from exile.)

Rimrock Knight

Rimrock Knight // Boulder Rush

Rider in Need

Create a 2/2 white Knight creature token with vigilance. (Then exile this card. You may cast the creature later from exile.)

Lonesome Unicorn

Lonesome Unicorn // Rider in Need

Venerable Knight

When this creature dies, put a +1/+1 counter on target Knight you control.

Weaselback Redcap

{1}{R}: This creature gets +2/+0 until end of turn.

Rowan's Battleguard

First strike
As long as you control a Rowan planeswalker, this creature gets +3/+0.