Celestial Mantle

Enchant creature
Enchanted creature gets +3/+3.
Whenever enchanted creature deals combat damage to a player, double its controller's life total.

Boonweaver Giant

When Boonweaver Giant enters, you may search your graveyard, hand, and/or library for an Aura card and put it onto the battlefield attached to Boonweaver Giant. If you search your library this way, shuffle.

Academy Researchers

When Academy Researchers enters, you may put an Aura card from your hand onto the battlefield attached to Academy Researchers.

Elder Mastery

Enchant creature
Enchanted creature gets +3/+3 and has flying.
Whenever enchanted creature deals damage to a player, that player discards two cards.

Through the Breach

You may put a creature card from your hand onto the battlefield. That creature gains haste. Sacrifice that creature at the beginning of the next end step.
Splice onto Arcane {2}{R}{R} (As you cast an Arcane spell, you may reveal this card from your hand and pay its splice cost. If you do, add this card's effects to that spell.)

Infinite Reflection

Enchant creature
When Infinite Reflection enters attached to a creature, each other nontoken creature you control becomes a copy of that creature.
Nontoken creatures you control enter as a copy of enchanted creature.

Colossification

Enchant creature
When Colossification enters, tap enchanted creature.
Enchanted creature gets +20/+20.

Sovereigns of Lost Alara

Exalted (Whenever a creature you control attacks alone, that creature gets +1/+1 until end of turn.)
Whenever a creature you control attacks alone, you may search your library for an Aura card that could enchant that creature, put it onto the battlefield attached to that creature, then shuffle.

Eldrazi Conscription

Enchant creature
Enchanted creature gets +10/+10 and has trample and annihilator 2. (Whenever it attacks, defending player sacrifices two permanents of their choice.)