Note the converted mana cost of each card as it's put into exile.
Bell Borca, Spectral Sergeant's power is equal to the greatest number noted for it this turn.
At the beginning of your upkeep, exile the top card of your library. You may play that card this turn.

Flying
, Sacrifice a Food: Target creature gets -3/-3 until end of turn.

When Demonic Lore enters the battlefield, draw three cards.
At the beginning of your end step, you lose 2 life for each card in your hand.

Flying

Target creature gets +2/+1 and gains flying until end of turn. (Then exile this card. You may cast the creature later from exile.)

When Kinsbaile Courier enters the battlefield, put a +1/+1 counter on target creature.
Encore (, Exile this card from your graveyard: For each opponent, create a token copy that attacks that opponent this turn if able. They gain haste. Sacrifice them at the beginning of the next end step. Activate only as a sorcery.)

Whenever Library Larcenist attacks, draw a card.

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for or one mana of that creature's color.)
When Martyr's Soul enters the battlefield, if you control no tapped lands, put two +1/+1 counters on it.

Choose a card name other than a basic land card name. Search target opponent's graveyard, hand, and library for any number of cards with that name and exile them. That player shuffles their library, then creates a 2/2 black Zombie creature token for each card exiled from their hand this way.

Flying
: Choose a color. Target opponent exiles the top X cards of their library. For each card of the chosen color exiled this way, create a 1/1 blue and black Faerie Rogue creature token with flying.

Enchant creature
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)
Whenever enchanted creature attacks, its controller loses 2 life and you gain 2 life.

Flash
Hexproof
When Slippery Bogbonder enters the battlefield, put a hexproof counter on target creature. Then move any number of counters from among creatures you control onto that creature.

Syr Elenora, the Discerning's power is equal to the number of cards in your hand.
When Syr Elenora enters the battlefield, draw a card.
Spells your opponents cast that target Syr Elenora cost more to cast.

When Tempting Witch enters the battlefield, create a Food token. (It's an artifact with ", , Sacrifice this artifact: You gain 3 life.")
, , Sacrifice a Food: Target player loses 3 life.

Tome of Legends enters the battlefield with a page counter on it.
Whenever your commander enters the battlefield or attacks, put a page counter on Tome of Legends.
, , Remove a page counter from Tome of Legends: Draw a card.

(Theme color: )

Enchant creature
When Winter's Rest enters the battlefield, tap enchanted creature.
As long as you control another snow permanent, enchanted creature doesn't untap during its controller's untap step.

(Theme color: )