Heartstone

Activated abilities of creatures cost {1} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Corpse Knight

Whenever another creature you control enters, each opponent loses 1 life.

Lurrus of the Dream-Den

Companion — Each permanent card in your starting deck has mana value 2 or less. (If this card is your chosen companion, you may put it into your hand from outside the game for {3} as a sorcery.)
Lifelink
Once during each of your turns, you may cast a permanent spell with mana value 2 or less from your graveyard.

Cruel Celebrant

Whenever Cruel Celebrant or another creature or planeswalker you control dies, each opponent loses 1 life and you gain 1 life.

High Market

{T}: Add {C}.
{T}, Sacrifice a creature: You gain 1 life.

Ashnod's Altar

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Tayam, Luminous Enigma

Each other creature you control enters with an additional vigilance counter on it.
{3}, Remove three counters from among creatures you control: Mill three cards, then return a permanent card with mana value 3 or less from your graveyard to the battlefield.

Eerie Ultimatum

Return any number of permanent cards with different names from your graveyard to the battlefield.

Blood Artist

Whenever Blood Artist or another creature dies, target player loses 1 life and you gain 1 life.

Damning Verdict

Destroy all creatures with no counters on them.

Cathars' Crusade

Whenever a creature you control enters, put a +1/+1 counter on each creature you control.

Gavony Township

{T}: Add {C}.
{2}{G}{W}, {T}: Put a +1/+1 counter on each creature you control.

Cauldron of Souls

{T}: Choose any number of target creatures. Each of those creatures gains persist until end of turn. (When it dies, if it had no -1/-1 counters on it, return it to the battlefield under its owner's control with a -1/-1 counter on it.)

Buried Alive

Search your library for up to three creature cards, put them into your graveyard, then shuffle.

Evolution Sage

Landfall — Whenever a land you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)