Roalesk, Apex Hybrid

Flying, trample
When Roalesk, Apex Hybrid enters, put two +1/+1 counters on another target creature you control.
When Roalesk dies, proliferate, then proliferate again. (Choose any number of permanents and/or players, then give each another counter of each kind already there. Then do it again.)

Ao, the Dawn Sky

Flying, vigilance
When Ao, the Dawn Sky dies, choose one —
• Look at the top seven cards of your library. Put any number of nonland permanent cards with total mana value 4 or less from among them onto the battlefield. Put the rest on the bottom of your library in a random order.
• Put two +1/+1 counters on each permanent you control that's a creature or Vehicle.

Wildsong Howler

Whenever this creature enters or transforms into Wildsong Howler, look at the top six cards of your library. You may reveal a creature card from among them and put it into your hand. Put the rest on the bottom of your library in a random order.
Nightbound (If a player casts at least two spells during their own turn, it becomes day next turn.)

Howlpack Piper

This spell can't be countered.
{1}{G}, {T}: You may put a creature card from your hand onto the battlefield. If it's a Wolf or Werewolf, untap Howlpack Piper. Activate only as a sorcery.
Daybound (If a player casts no spells during their own turn, it becomes night next turn.)

Howlpack Piper // Wildsong Howler

Deathrender

Equipped creature gets +2/+2.
Whenever equipped creature dies, you may put a creature card from your hand onto the battlefield and attach Deathrender to it.
Equip {2}

Delighted Halfling

{T}: Add {C}.
{T}: Add one mana of any color. Spend this mana only to cast a legendary spell, and that spell can't be countered.

Zoological Study

Mill five cards, then return a creature card milled this way to your hand. (Then exile this card. You may cast the artifact later from exile.)

Monster Manual

{1}{G}, {T}: You may put a creature card from your hand onto the battlefield.

Monster Manual // Zoological Study

Champion of Rhonas

You may exert Champion of Rhonas as it attacks. When you do, you may put a creature card from your hand onto the battlefield. (An exerted creature won't untap during your next untap step.)

Brenard, Ginger Sculptor

Each creature you control that's a Food or a Golem gets +2/+2 and has trample.
Whenever another nontoken creature you control dies, you may exile it. If you do, create a token that's a copy of that creature, except it's a 1/1 Food Golem artifact creature in addition to its other types and it has "{2}, {T}, Sacrifice this artifact: You gain 3 life."

Aetherplasm

Whenever Aetherplasm blocks a creature, you may return Aetherplasm to its owner's hand. If you do, you may put a creature card from your hand onto the battlefield blocking that creature.