Demonic Vigor

Enchant creature
Enchanted creature gets +1/+1.
When enchanted creature dies, return that card to its owner's hand.

Firebreathing

Enchant creature
{R}: Enchanted creature gets +1/+0 until end of turn.

Enchant artifact or creature
As long as enchanted permanent is a creature, it gets +2/+1.

Enchant creature
Enchanted creature gets +2/+1 and has menace. (It can't be blocked except by two or more creatures.)

Flash
Enchant creature
Enchanted creature gets +2/+0.
When enchanted creature dies, return it to the battlefield tapped under its owner's control.

Enchant creature
When Dark Favor enters the battlefield, you lose 1 life.
Enchanted creature gets +3/+1.

Enchant creature
Enchanted creature gets +2/+2 and has haste.

Enchant creature
Enchanted creature gets +2/+0 and has "{2}{B}: Regenerate this creature."