Bloated Contaminator

Trample
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever Bloated Contaminator deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Ticketomaton

When Ticketomaton enters, you get {TK}, then you may put a sticker on a nonland permanent you own.

Contentious Plan

Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
Draw a card.

Chicken Troupe

Ward {2} (Whenever this creature becomes the target of a spell or ability an opponent controls, counter it unless that player pays {2}.)
When Chicken Troupe enters, you get {TK}, then you may put a sticker on a nonland permanent you own.

Flux Channeler

Whenever you cast a noncreature spell, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Evolution Sage

Landfall — Whenever a land you control enters, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Arcane Signet

{T}: Add one mana of any color in your commander's color identity.

Stiltstrider

Reach
When Stiltstrider enters, you get {TK}{TK}, then you may put a sticker on a nonland permanent you own.

Nature's Lore

Search your library for a Forest card, put that card onto the battlefield, then shuffle.

Simic Signet

Clandestine Chameleon

When Clandestine Chameleon enters, you get {TK}{TK}, then you may put a sticker on a nonland permanent you own.
Clandestine Chameleon has all abilities of ability stickers on other permanents you own and cards in your graveyard.

Kodama's Reach

Search your library for up to two basic land cards, reveal those cards, put one onto the battlefield tapped and the other into your hand, then shuffle.

Baaallerina

Flying
When Baaallerina enters, you may put a name sticker on a nonland permanent you own.
{2}{U}: Another target creature with a name sticker on it gains flying until end of turn.

Bioluminary

Whenever Bioluminary deals combat damage to a player, you get {TK}{TK}, then you may put a sticker on a nonland permanent you own.

Guildpact Informant

Flying
Whenever Guildpact Informant deals combat damage to a player or planeswalker, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Wicker Picker

Creature spells you cast have sticker kicker {1}. (You may pay an additional {1} as you cast a creature spell. If you do, you get {TK}, then you may put a sticker on it.)

Wizards of the _____

When this creature enters, you may put a name sticker on it, then look at the top X cards of your library, where X is the number of unique vowels on that sticker. Put one of those cards into your hand and the rest on the bottom of your library in any order. (The vowels are A, E, I, O, U, and Y.)

Ripples of Potential

Proliferate, then choose any number of permanents you control that had a counter put on them this way. Those permanents phase out. (To proliferate, choose any number of permanents and/or players, then give each another counter of each kind already there. Treat phased-out permanents and anything attached to them as though they don't exist until their controller's next turn.)

Ticket Turbotubes

{T}: Add one mana of any color.
{3}, {T}: You get {TK} (a ticket counter).

Monitor Monitor

When Monitor Monitor enters, open an Attraction. (Put the top card of your Attraction deck onto the battlefield.)
Once each turn, you may pay {1} to reroll one or more dice you rolled.

Unnatural Restoration

Return target permanent card from your graveyard to your hand. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Growth Spiral

Draw a card. You may put a land card from your hand onto the battlefield.

Planar Incision

Exile target artifact or creature, then return it to the battlefield under its owner's control with a +1/+1 counter on it.

Staff of Compleation

{T}, Pay 1 life: Destroy target permanent you own.
{T}, Pay 2 life: Add one mana of any color.
{T}, Pay 3 life: Proliferate.
{T}, Pay 4 life: Draw a card.
{5}: Untap Staff of Compleation.

Petting Zookeeper

Reach
When Petting Zookeeper enters, open an Attraction. (Put the top card of your Attraction deck onto the battlefield.)

Ambassador Blorpityblorpboop

When Ambassador Blorpityblorpboop enters, you get {TK}{TK}{TK}, then you may put a sticker on a nonland permanent you own.
At the beginning of each combat, you may have Ambassador Blorpityblorpboop's base power become equal to the total power of all stickers on permanents you control and its base toughness become equal to those stickers' total toughness.

Coming Attraction

Search your library for a basic land card, put it onto the battlefield tapped, then shuffle. Open an Attraction. (Put the top card of your Attraction deck onto the battlefield.)

Thrummingbird

Flying
Whenever Thrummingbird deals combat damage to a player, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Tezzeret's Gambit

({U/P} can be paid with either {U} or 2 life.)
Draw two cards, then proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Lineprancers

When Lineprancers enters, you get {TK}{TK}, then you may put a power and toughness sticker on a creature you own.
{3}{G}: Target creature you don't control blocks target creature you control with a power and toughness sticker on it other than Lineprancers this turn if able.

Carnival Elephant Meteor

{TK}{TK} — Sacrifice this permanent: Draw two cards.
{TK}{TK}{TK} — Whenever this creature attacks, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)
{TK}{TK} — 4/1
{TK}{TK}{TK}{TK}{TK} — 8/7

Dreamtide Whale

Vanishing 2 (This creature enters with two time counters on it. At the beginning of your upkeep, remove a time counter from it. When the last is removed, sacrifice it.)
Whenever a player casts their second spell each turn, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Tainted Observer

Flying
Toxic 1 (Players dealt combat damage by this creature also get a poison counter.)
Whenever another creature you control enters, you may pay {2}. If you do, proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Finishing Move

You get {TK}{TK}, then you may put a sticker on a nonland permanent you own. Target creature you control deals damage equal to its power to target creature you don't control.

Blur

Exile target creature you control, then return that card to the battlefield under its owner's control.
Draw a card.

_____-o-saurus

Trample
When this creature enters, you may put a name sticker on it. Put a +1/+1 counter on it for each unique vowel on that sticker. (The vowels are A, E, I, O, U, and Y.)

Key to the City

{T}, Discard a card: Up to one target creature can't be blocked this turn.
Whenever Key to the City becomes untapped, you may pay {2}. If you do, draw a card.

Contaminant Grafter

Trample, toxic 1
Whenever one or more creatures you control deal combat damage to one or more players, proliferate.
Corrupted — At the beginning of your end step, if an opponent has three or more poison counters, draw a card, then you may put a land card from your hand onto the battlefield.

Experimental Augury

Look at the top three cards of your library. Put one of them into your hand and the rest on the bottom of your library in any order. Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Done for the Day

At the beginning of your end step, if you control an Employee, a Performer, or a Robot, you may get {TK} or create a Treasure token. If you control all three, you may put a sticker on a nonland permanent you own.

Sol Ring

Displace

Exile up to two target creatures you control, then return those cards to the battlefield under their owner's control.

Command Performance

Choose two —
• Open an Attraction. (Put the top card of your Attraction deck onto the battlefield.)
• Roll to visit your Attractions.
• You get {TK}{TK}.
• You may put a sticker on a nonland permanent you own.

Blorbian Buddy

Trample
{G}, {T}: You get {TK} (a ticket counter).

Cankerbloom

{1}, Sacrifice Cankerbloom: Choose one —
• Destroy target artifact.
• Destroy target enchantment.
• Proliferate. (Choose any number of permanents and/or players, then give each another counter of each kind already there.)

Sword Coast Sailor

Commander creatures you own have "Whenever this creature attacks a player, if no opponent has more life than that player, this creature can't be blocked this turn."