March of the Machines

Each noncreature artifact is an artifact creature with power and toughness each equal to its mana value. (Equipment that's a creature can't equip a creature.)

Opalescence

Each other non-Aura enchantment is a creature in addition to its other types and has base power and base toughness each equal to its mana value.

Humility

All creatures lose all abilities and have base power and toughness 1/1.

Monkey Cage

When a creature enters, sacrifice this artifact and create X 2/2 green Monkey creature tokens, where X is that creature's mana value.

Felidar Guardian

When this creature enters, you may exile another target permanent you control, then return that card to the battlefield under its owner's control.

Cleansing Meditation

Destroy all enchantments.
Threshold — If there are seven or more cards in your graveyard, instead destroy all enchantments, then return all cards in your graveyard destroyed this way to the battlefield.

Starfield of Nyx

At the beginning of your upkeep, you may return target enchantment card from your graveyard to the battlefield.
As long as you control five or more enchantments, each other non-Aura enchantment you control is a creature in addition to its other types and has base power and base toughness each equal to its mana value.

Portcullis

Whenever a creature enters, if there are two or more other creatures on the battlefield, exile that creature. Return that card to the battlefield under its owner's control when this artifact leaves the battlefield.

Grand Arbiter Augustin IV

White spells you cast cost {1} less to cast.
Blue spells you cast cost {1} less to cast.
Spells your opponents cast cost {1} more to cast.

Dovescape

({W/U} can be paid with either {W} or {U}.)
Whenever a player casts a noncreature spell, counter that spell. That player creates X 1/1 white and blue Bird creature tokens with flying, where X is the spell's mana value.

Parallax Wave

Fading 5 (This enchantment enters with five fade counters on it. At the beginning of your upkeep, remove a fade counter from it. If you can't, sacrifice it.)
Remove a fade counter from this enchantment: Exile target creature.
When this enchantment leaves the battlefield, each player returns to the battlefield all cards they own exiled with it.