Creeping Bloodsucker

At the beginning of your upkeep, Creeping Bloodsucker deals 1 damage to each opponent. You gain life equal to the damage dealt this way.

Wernog, Rider's Chaplain

When Wernog, Rider's Chaplain enters or leaves the battlefield, each opponent may investigate. Each opponent who doesn't loses 1 life. You investigate X times, where X is one plus the number of opponents who investigated this way.
Friends forever (You can have two commanders if both have friends forever.)

Bartolomé del Presidio

Sacrifice another creature or artifact: Put a +1/+1 counter on Bartolomé del Presidio.

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Welcoming Vampire

Flying
Whenever one or more other creatures you control with power 2 or less enter, draw a card. This ability triggers only once each turn.

Sol Ring

Agent of the Iron Throne

Commander creatures you own have "Whenever an artifact or creature you control is put into a graveyard from the battlefield, each opponent loses 1 life."

Teysa, Opulent Oligarch

Deathtouch
At the beginning of your end step, investigate for each opponent who lost life this turn.
Whenever a Clue you control is put into a graveyard from the battlefield, create a 1/1 white and black Spirit creature token with flying. This ability triggers only once each turn.

Wispdrinker Vampire

Flying
Whenever another creature you control with power 2 or less enters, each opponent loses 1 life and you gain 1 life.
{5}{W}{B}: Creatures you control with power 2 or less gain deathtouch and lifelink until end of turn.

Talisman of Hierarchy

{T}: Add {C}.
{T}: Add {W} or {B}. Talisman of Hierarchy deals 1 damage to you.

Mirkwood Bats

Flying
Whenever you create or sacrifice a token, each opponent loses 1 life.

Delney, Streetwise Lookout

Creatures you control with power 2 or less can't be blocked by creatures with power 3 or greater.
If an ability of a creature you control with power 2 or less triggers, that ability triggers an additional time.

Lich-Knights' Conquest

Sacrifice any number of artifacts, enchantments, and/or tokens. Return that many creature cards from your graveyard to the battlefield.