Breathkeeper Seraph

Flying, soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Breathkeeper Seraph is paired with another creature, each of those creatures has "When this creature dies, you may return it to the battlefield under its owner's control at the beginning of your next upkeep."

Have

Evolving Wilds

{T}, Sacrifice Evolving Wilds: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Indomitable Will

Flash
Enchant creature
Enchanted creature gets +1/+2.

Erase

Fortifying Provisions

Creatures you control get +0/+1.
When Fortifying Provisions enters, create a Food token. (It's an artifact with "{2}, {T}, Sacrifice this artifact: You gain 3 life.")

Don't Have

Resplendent Angel

Flying
At the beginning of each end step, if you gained 5 or more life this turn, create a 4/4 white Angel creature token with flying and vigilance.
{3}{W}{W}{W}: Until end of turn, Resplendent Angel gets +2/+2 and gains lifelink.

Getting

Lyra Dawnbringer

Flying, first strike, lifelink
Other Angels you control get +1/+1 and have lifelink.

Triumphant Surge

Destroy target creature with power 4 or greater. You gain 3 life.

Holy Day

Prevent all combat damage that would be dealt this turn.

Angel's Mercy

Sandblast

Sandblast deals 5 damage to target attacking or blocking creature.

Disenchant

Plains

Youthful Valkyrie

Flying
Whenever another Angel you control enters, put a +1/+1 counter on Youthful Valkyrie.

Dawning Angel

Flying
When Dawning Angel enters, you gain 4 life.

Cloudshift

Exile target creature you control, then return that card to the battlefield under your control.

Fabled Passage

{T}, Sacrifice Fabled Passage: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Then if you control four or more lands, untap that land.

Silverflame Ritual

Put a +1/+1 counter on each creature you control.
Adamant — If at least three white mana was spent to cast this spell, creatures you control gain vigilance until end of turn.

Feat of Resistance

Put a +1/+1 counter on target creature you control. It gains protection from the color of your choice until end of turn. (It can't be blocked, targeted, dealt damage, enchanted, or equipped by anything of that color.)

Glaring Aegis

Enchant creature
When Glaring Aegis enters, tap target creature an opponent controls.
Enchanted creature gets +1/+3.

Angelic Quartermaster

Flying
When Angelic Quartermaster enters, put a +1/+1 counter on each of up to two other target creatures.

Sigarda's Summons

Creatures you control with +1/+1 counters on them have base power and toughness 4/4, have flying, and are Angels in addition to their other types.

Angel of the Dawn

Flying
When Angel of the Dawn enters, creatures you control get +1/+1 and gain vigilance until end of turn.

Prism Ring

As Prism Ring enters, choose a color.
Whenever you cast a spell of the chosen color, you gain 1 life.

Revoke Existence

Aerial Assault

Destroy target tapped creature. You gain 1 life for each creature you control with flying.

Outflank

Outflank deals damage to target attacking or blocking creature equal to the number of creatures you control.