Nesting Dovehawk

Flying
At the beginning of combat on your turn, populate. (Create a token that's a copy of a creature token you control.)
Whenever a creature token you control enters, put a +1/+1 counter on Nesting Dovehawk.

Hour of Reckoning

Convoke (Your creatures can help cast this spell. Each creature you tap while casting this spell pays for {1} or one mana of that creature's color.)
Destroy all nontoken creatures.

Echoing Assault

Creature tokens you control have menace.
Whenever you attack a player, choose target nontoken creature that's attacking that player. Create a token that's a copy of that creature, except it's 1/1. The token enters tapped and attacking that player. Sacrifice it at the beginning of the next end step.

Skycat Sovereign

Flying
Skycat Sovereign gets +1/+1 for each other creature you control with flying.
{2}{W}{U}: Create a 1/1 white Cat Bird creature token with flying.

Toby, Beastie Befriender

When Toby, Beastie Befriender enters, create a 4/4 white Beast creature token with "This creature can't attack or block alone."
As long as you control four or more creature tokens, creature tokens you control have flying.

Warleader's Call

Creatures you control get +1/+1.
Whenever a creature you control enters, Warleader's Call deals 1 damage to each opponent.

Dazzling Denial

Counter target spell unless its controller pays {2}. If you control a Bird, counter that spell unless its controller pays {4} instead.

Kykar, Wind's Fury

Flying
Whenever you cast a noncreature spell, create a 1/1 white Spirit creature token with flying.
Sacrifice a Spirit: Add {R}.

Brudiclad, Telchor Engineer

Creature tokens you control have haste.
At the beginning of combat on your turn, create a 2/1 blue Phyrexian Myr artifact creature token. Then you may choose a token you control. If you do, each other token you control becomes a copy of that token.

Murmuration

Birds you control get +1/+1 and have vigilance.
At the beginning of your end step, for each spell you've cast this turn, create a 1/2 blue Bird creature token with flying named Storm Crow.

Mondrak, Glory Dominus

If one or more tokens would be created under your control, twice that many of those tokens are created instead.
{1}{W/P}{W/P}, Sacrifice two other artifacts and/or creatures: Put an indestructible counter on Mondrak, Glory Dominus. ({W/P} can be paid with either {W} or 2 life.)

Zinnia, Valley's Voice

Flying
Zinnia, Valley's Voice gets +X/+0, where X is the number of other creatures you control with base power 1.
Creature spells you cast have offspring {2}. (You may pay an additional {2} as you cast a creature spell. If you do, when that creature enters, create a 1/1 token copy of it.)

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice Idol of Oblivion: Create a 10/10 colorless Eldrazi creature token.

Aven Wind Guide

Flying, vigilance
Creature tokens you control have flying and vigilance.
Embalm {4}{W}{U} ({4}{W}{U}, Exile this card from your graveyard: Create a token that's a copy of it, except it's a white Zombie Bird Warrior with no mana cost. Embalm only as a sorcery.)

Curiosity Crafter

Flying
You have no maximum hand size.
Whenever a creature token you control deals combat damage to a player, draw a card.

Prismari Campus

Prismari Campus enters tapped.
{T}: Add {U} or {R}.
{4}, {T}: Scry 1.

Intangible Virtue

Creature tokens you control get +1/+1 and have vigilance.

Agate Instigator

Offspring {1}{R} (You may pay an additional {1}{R} as you cast this spell. If you do, when this creature enters, create a 1/1 token copy of it.)
Whenever another creature you control enters, this creature deals 1 damage to each opponent.

Rootborn Defenses

Populate. Creatures you control gain indestructible until end of turn. (To populate, create a token that's a copy of a creature token you control.)

Kastral, the Windcrested

Flying
Whenever one or more Birds you control deal combat damage to a player, choose one —
• You may put a Bird creature card from your hand or graveyard onto the battlefield with a finality counter on it.
• Put a +1/+1 counter on each Bird you control.
• Draw a card.

The Locust God

Flying
Whenever you draw a card, create a 1/1 blue and red Insect creature token with flying and haste.
{2}{U}{R}: Draw a card, then discard a card.
When The Locust God dies, return it to its owner's hand at the beginning of the next end step.

Akim, the Soaring Wind

Flying
Whenever you create one or more tokens for the first time each turn, create a 1/1 white Bird creature token with flying.
{3}{U}{R}{W}: Creature tokens you control gain double strike until end of turn.