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.)

Hakim, Loreweaver

Flying
{U}{U}: Return target Aura card from your graveyard to the battlefield attached to Hakim. Activate only during your upkeep and only if Hakim isn't enchanted.
{U}{U}, {T}: Destroy all Auras attached to Hakim.

Rousing Read

Enchant creature
When this Aura enters, draw two cards, then discard a card.
Enchanted creature gets +1/+1 and has flying.

Octopus Umbra

Enchant creature
Enchanted creature has base power and toughness 8/8 and has "Whenever this creature attacks, you may tap target creature with power 8 or less."
Umbra armor (If enchanted creature would be destroyed, instead remove all damage from it and destroy this Aura.)

Corrupted Conscience

Enchant creature
You control enchanted creature.
Enchanted creature has infect. (It deals damage to creatures in the form of -1/-1 counters and to players in the form of poison counters.)