Heart's Desire

Create a 1/1 white Human creature token. (Then exile this card. You may cast the creature later from exile.)

Lovestruck Beast

Lovestruck Beast can't attack unless you control a 1/1 creature.

Whenever you cast a creature spell that has an Adventure, draw a card. (It doesn't need to have gone on the adventure first.)

Destroy target creature or planeswalker. You lose 2 life. (Then exile this card. You may cast the creature later from exile.)

Lifelink
When Murderous Rider dies, put it on the bottom of its owner's library.

Whenever you cast an Adventure instant or sorcery spell, copy it. You may choose new targets for the copy.

You draw a card and you lose 1 life. (Then exile this card. You may cast the creature later from exile.)

You gain X life and each opponent loses X life, where X is the number of Knights you control.

Return target creature card from your graveyard to your hand. (Then exile this card. You may cast the creature later from exile.)