Security Bypass

Enchant creature
As long as enchanted creature is attacking alone, it can't be blocked.
Enchanted creature has "Whenever this creature deals combat damage to a player, it connives." (Its controller draws a card, then discards a card. If they discarded a nonland card, they put a +1/+1 counter on this creature.)

Plains

Spara's Headquarters

({T}: Add {G}, {W}, or {U}.)
Spara's Headquarters enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Skybridge Towers

Skybridge Towers enters tapped.
{T}: Add {W} or {U}.
{2}{W}{U}, {T}, Sacrifice Skybridge Towers: Draw a card.

Brokers Initiate

{4}{G/U}: Brokers Initiate has base power and toughness 5/5 until end of turn.

Witness Protection

Enchant creature
Enchanted creature loses all abilities and is a green and white Citizen creature with base power and toughness 1/1 named Legitimate Businessperson. (It loses all other colors, card types, creature types, and names.)

Take to the Streets

Creatures you control get +2/+2 until end of turn. Citizens you control get an additional +1/+1 and gain vigilance until end of turn.

Island

Brokers Ascendancy

At the beginning of your end step, put a +1/+1 counter on each creature you control and a loyalty counter on each planeswalker you control.

Backup Agent

When Backup Agent enters, put a +1/+1 counter on target creature.

Brokers Hideout

When Brokers Hideout enters, sacrifice it. When you do, search your library for a basic Forest, Plains, or Island card, put it onto the battlefield tapped, then shuffle and you gain 1 life.

Forest

Disciplined Duelist

Double strike
Disciplined Duelist enters with a shield counter on it. (If it would be dealt damage or destroyed, remove a shield counter from it instead.)

Citizen's Crowbar

When Citizen's Crowbar enters, create a 1/1 green and white Citizen creature token, then attach Citizen's Crowbar to it.
Equipped creature gets +1/+1 and has "{W}, {T}, Sacrifice Citizen's Crowbar: Destroy target artifact or enchantment."
Equip {2} ({2}: Attach to target creature you control. Equip only as a sorcery.)

Lagrella, the Magpie

When Lagrella, the Magpie enters, exile any number of other target creatures controlled by different players until Lagrella leaves the battlefield. When an exiled card enters under your control this way, put two +1/+1 counters on it.

Botanical Plaza

Botanical Plaza enters tapped.
{T}: Add {G} or {W}.
{2}{G}{W}, {T}, Sacrifice Botanical Plaza: Draw a card.

Darling of the Masses

Other Citizens you control get +1/+0.
Whenever Darling of the Masses attacks, create a 1/1 green and white Citizen creature token.

Ceremonial Groundbreaker

Equipped creature gets +2/+1 and has trample.
Equip Citizen {1}
Equip {3} ({3}: Attach to target creature you control. Equip only as a sorcery.)

Gathering Throng

When Gathering Throng enters, you may search your library for any number of cards named Gathering Throng, reveal them, put them into your hand, then shuffle.

Hold for Ransom

Enchant creature
Enchanted creature can't attack or block and has "{7}: Hold for Ransom's controller sacrifices it and draws a card. Activate only as a sorcery."

Civil Servant

Whenever Civil Servant attacks, you may tap another untapped Citizen you control. If you do, Civil Servant gets +1/+0 and gains lifelink until end of turn.