I like morph on noncreatures here. It gives you two types of permanents to choose from.
We could bring back Transmute as a way to make one card type into another.
Mercurial – Whenever an artifact, creature, enchantment, or land enters the battlefield, this card becomes that card's card types in addition to its other types until end of turn. As long as it's a creature, it's a 2/2. As long as it's a land, it has "
: Add
to your mana pool."
Animate [1] (As long as this permanent has a +1/+1 counter on it, it is a 0/0 Artifact Creature in addition to its other types.)
Fleeting (Whenever you cast an instant spell, you may return this permanent to its owner's hand.)
[If/As long as] you have mastery, [Effect]. (You have mastery as long as you control an artifact, a creature, an enchantment, and a land.)
Mastery—[Ability] (Activate this ability only if you control an artifact, a creature, an enchantment, and a land.)
[Card type] tribute (You may cast a [card type] spell by sacrificing this and paying the difference in mana costs between that card and this one.)
[Card type] bringer (When this permanent enters the battlefield, you may cast a [card type] card from your hand with converted mana cost less than that of this card without paying its mana cost.)
Animate [1] (As long as this permanent has a +1/+1 counter on it, it is a 0/0 Artifact Creature in addition to its other types.)
Animate [2] target permanent (It becomes a 2/2 creature until end of turn. It retains all other types and abilities)
Animate [3] (as long as ~ has a +1/+1 counter on it, it is a creature with power and toughness equal to its converted mana cost)
Rituals
Runes of Protection Enchantment - Ritual(At the beginning of your upkeep, reduce ~'s duration by 1. ~ ends when its duration becomes 0.)Creatures you control get +0/+2.
2Essentia
Runes of Protection EnchantmentCreatures you control get +0/+2.
Essentia 3/3
(You may cast this spell as a sorcery with "Put a colorless 3/3 Spirit creature token onto the battlefield.)Caldera Sabertooth Creature—Elemental Cat (U)
Blitz
(If you cast this spell for its blitz cost, it has haste. Sacrifice it at the beginning of the next end step.)Each creature card in your hand has blitz. The blitz cost is equal to its mana cost reduced by
.
3/1
Surge
Runes of Protection EnchantmentSurge
(You may cast this card for it's Surge cost. If you do, it enters the battlefield with haste. Sacrifice it at the beginning of the next upkeep.)Creatures you control get +0/+2.
Animate [4]
Runes of Protection EnchantmentAnimate [4] - Creatures you control get +0/+2.
(You may have ~ enter the battlefield as a creature in addition to it's other types. If you do, it loses this ability.)3/5CreatureErupt
—~ deals 2 damage to target creature.
(You may cast this card for its erupt cost from your hand or from the battlefield. If you do, it's an instant spell with the given text.)2/1
Permanents that are spells.
Just wanted to gather all the keywords submitted so far together into one post.