Dimir Guildgate

Dimir Guildgate enters tapped.
{T}: Add {U} or {B}.

Persistent Petitioners

{1}, {T}: Target player mills a card. (They put the top card of their library into their graveyard.)
Tap four untapped Advisors you control: Target player mills twelve cards.
A deck can have any number of cards named Persistent Petitioners.

Cast Down

Rat Colony

Rat Colony gets +1/+0 for each other Rat you control.
A deck can have any number of cards named Rat Colony.

Gateway Plaza

Gateway Plaza enters tapped.
When Gateway Plaza enters, sacrifice it unless you pay {1}.
{T}: Add one mana of any color.

Island

Wall of Lost Thoughts

Defender
When Wall of Lost Thoughts enters, target player mills four cards.

Psychic Corrosion

Whenever you draw a card, each opponent mills two cards.

Swamp

Thought Collapse

Counter target spell. Its controller mills three cards.

Guild Summit

When Guild Summit enters, you may tap any number of untapped Gates you control. Draw a card for each Gate tapped this way.
Whenever a Gate you control enters, draw a card.