Rampant Growth

Search your library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Plains

Tamiyo's Journal

At the beginning of your upkeep, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
{T}, Sacrifice three Clues: Search your library for a card, put that card into your hand, then shuffle.

Sophia, Dogged Detective

When Sophia enters, create Tiny, a legendary 2/2 green Dog Detective creature token with trample.
{1}, Sacrifice an artifact token: Put a +1/+1 counter on each Dog you control.
Whenever a Dog you control deals combat damage to a player, create a Food token, then investigate.

Search the Premises

Whenever a creature attacks you or a planeswalker you control, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Sea of Clouds

This land enters tapped unless you have two or more opponents.
{T}: Add {W} or {U}.

Spara's Headquarters

({T}: Add {G}, {W}, or {U}.)
This land enters tapped.
Cycling {3} ({3}, Discard this card: Draw a card.)

Officious Interrogation

This spell costs {W}{U} more to cast for each target beyond the first.
Choose any number of target players. Investigate X times, where X is the total number of creatures those players control.

Ongoing Investigation

Whenever one or more creatures you control deal combat damage to a player, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
{1}{G}, Exile a creature card from your graveyard: Investigate. You gain 2 life.

Dreamroot Cascade

This land enters tapped unless you control two or more other lands.
{T}: Add {G} or {U}.

Hardened Scales

If one or more +1/+1 counters would be put on a creature you control, that many plus one +1/+1 counters are put on it instead.

Glacial Fortress

This land enters tapped unless you control a Plains or an Island.
{T}: Add {W} or {U}.

Release the Dogs

Create four 1/1 white Dog creature tokens.

Bred for the Hunt

Whenever a creature you control with a +1/+1 counter on it deals combat damage to a player, you may draw a card.

Three Visits

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

Inspiring Statuary

Nonartifact spells you cast have improvise. (Your artifacts can help cast those spells. Each artifact you tap after you're done activating mana abilities pays for {1}.)

Prairie Stream

({T}: Add {W} or {U}.)
This land enters tapped unless you control two or more basic lands.

Idol of Oblivion

{T}: Draw a card. Activate only if you created a token this turn.
{8}, {T}, Sacrifice this artifact: Create a 10/10 colorless Eldrazi creature token.

Resolute Watchdog

Defender
{1}, Sacrifice this creature: Target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Canopy Vista

({T}: Add {G} or {W}.)
This land enters tapped unless you control two or more basic lands.

Isamaru, Hound of Konda

Maskwood Nexus

Creatures you control are every creature type. The same is true for creature spells you control and creature cards you own that aren't on the battlefield.
{3}, {T}: Create a 2/2 blue Shapeshifter creature token with changeling. (It is every creature type.)

District Mascot

This creature enters with a +1/+1 counter on it.
{1}{G}, Remove two +1/+1 counters from this creature: Destroy target artifact.
Whenever this creature attacks while saddled, put a +1/+1 counter on it.
Saddle 1

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.

Blink Dog

Double strike
Teleport — {3}{W}: This creature phases out. (Treat it and anything attached to it as though they don't exist until your next turn.)

Exotic Orchard

{T}: Add one mana of any color that a land an opponent controls could produce.

Alpine Watchdog

Vigilance (Attacking doesn't cause this creature to tap.)

Command Tower

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

Pack Leader

Other Dogs you control get +1/+1.
Whenever this creature attacks, prevent all combat damage that would be dealt this turn to Dogs you control.

Wary Watchdog

When this creature enters or dies, surveil 1. (Look at the top card of your library. You may put it into your graveyard.)

Swords to Plowshares

Exile target creature. Its controller gains life equal to its power.

Jaheira, Friend of the Forest

Tokens you control have "{T}: Add {G}."
Choose a Background (You can have a Background as a second commander.)

Rejuvenating Springs

This land enters tapped unless you have two or more opponents.
{T}: Add {G} or {U}.

Rambunctious Mutt

When this creature enters, destroy target artifact or enchantment an opponent controls.

Mowu, Loyal Companion

Vigilance, trample
If one or more +1/+1 counters would be put on Mowu, that many plus one +1/+1 counters are put on it instead.

Path of Ancestry

This land enters tapped.
{T}: Add one mana of any color in your commander's color identity. When that mana is spent to cast a creature spell that shares a creature type with your commander, scry 1. (Look at the top card of your library. You may put that card on the bottom.)

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.

Peregrin Took

If one or more tokens would be created under your control, those tokens plus an additional Food token are created instead. (It's an artifact with "{2}, {T}, Sacrifice this token: You gain 3 life.")
Sacrifice three Foods: Draw a card.

Kindred Discovery

As this enchantment enters, choose a creature type.
Whenever a creature you control of the chosen type enters or attacks, draw a card.

Animal Sanctuary

{T}: Add {C}.
{2}, {T}: Put a +1/+1 counter on target Bird, Cat, Dog, Goat, Ox, or Snake.

Loyal Warhound

Vigilance
When this creature enters, if an opponent controls more lands than you, search your library for a basic Plains card, put it onto the battlefield tapped, then shuffle.

Beast Within

Destroy target permanent. Its controller creates a 3/3 green Beast creature token.

Greater Tanuki

Trample
Channel — {2}{G}, Discard this card: Search your library for a basic land card, put it onto the battlefield tapped, then shuffle.

Tanuki Transplanter

Whenever this creature or equipped creature attacks, add an amount of {G} equal to its power. Until end of turn, you don't lose this mana as steps and phases end.
Reconfigure {3} ({3}: Attach to target creature you control; or unattach from a creature. Reconfigure only as a sorcery. While attached, this isn't a creature.)

Arcane Signet

Longshot Squad

Outlast {1}{G} ({1}{G}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each creature you control with a +1/+1 counter on it has reach. (A creature with reach can block creatures with flying.)

Supply Runners

When this creature enters, put a +1/+1 counter on each other creature you control.

Generous Pup

Vigilance
Whenever one or more +1/+1 counters are put on this creature, put a +1/+1 counter on each other creature you control. This ability triggers only once each turn.

Generous Gift

Destroy target permanent. Its controller creates a 3/3 green Elephant creature token.

Cultivate

Ainok Bond-Kin

Outlast {1}{W} ({1}{W}, {T}: Put a +1/+1 counter on this creature. Outlast only as a sorcery.)
Each creature you control with a +1/+1 counter on it has first strike.

Selfless Savior

Sacrifice this creature: Another target creature you control gains indestructible until end of turn. (Damage and effects that say "destroy" don't destroy it.)

Patchwork Banner

As this artifact enters, choose a creature type.
Creatures you control of the chosen type get +1/+1.
{T}: Add one mana of any color.

Hallowed Fountain

({T}: Add {W} or {U}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Spirited Companion

Phelia, Exuberant Shepherd

Flash
Whenever Phelia attacks, exile up to one other target nonland permanent. At the beginning of the next end step, return that card to the battlefield under its owner's control. If it entered under your control, put a +1/+1 counter on Phelia.

Inspiring Call

Draw a card for each creature you control with a +1/+1 counter on it. Those creatures gain indestructible until end of turn. (Damage and effects that say "destroy" don't destroy them.)

Hinterland Harbor

This land enters tapped unless you control a Forest or an Island.
{T}: Add {G} or {U}.

Faithful Watchdog

Vigilance
This creature enters with three +1/+1 counters on it.

Farseek

Search your library for a Plains, Island, Swamp, or Mountain card, put it onto the battlefield tapped, then shuffle.

Mischievous Pup

Flash (You may cast this spell any time you could cast an instant.)
When this creature enters, return up to one other target permanent you control to its owner's hand.

Krovod Haunch

Equipped creature gets +2/+0.
{2}, {T}, Sacrifice this Equipment: You gain 3 life.
When this Equipment is put into a graveyard from the battlefield, you may pay {1}{W}. If you do, create two 1/1 white Dog creature tokens.
Equip {2}

Floodhound

{3}, {T}: Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Mordenkainen

+2: Draw two cards, then put a card from your hand on the bottom of your library.
−2: Create a blue Dog Illusion creature token with "This token's power and toughness are each equal to twice the number of cards in your hand."
−10: Exchange your hand and library, then shuffle. You get an emblem with "You have no maximum hand size."

Sol Ring

Academy Manufactor

If you would create a Clue, Food, or Treasure token, instead create one of each.

Disorder in the Court

Exile X target creatures, then investigate X times. Return the exiled cards to the battlefield tapped under their owners' control at the beginning of the next end step. (To investigate, create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Rex, Cyber-Hound

Whenever Rex deals combat damage to a player, they mill two cards and you get {E}{E} (two energy counters).
Pay {E}{E}: Choose target creature card in a graveyard. Exile it with a brain counter on it. Activate only as a sorcery.
Rex has all activated abilities of all cards in exile with brain counters on them.

Forest

Temple Garden

({T}: Add {G} or {W}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Mushroom Watchdogs

Sacrifice a Food: Put a +1/+1 counter on this creature. It gains vigilance until end of turn. Activate only as a sorcery.

Nature's Lore

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

Seaside Citadel

This land enters tapped.
{T}: Add {G}, {W}, or {U}.

Trusty Retriever

When this creature enters, choose one —
• Put a +1/+1 counter on this creature.
• Return target artifact or enchantment card from your graveyard to your hand.

Yoshimaru, Ever Faithful

Whenever another legendary permanent you control enters, put a +1/+1 counter on Yoshimaru.
Partner (You can have two commanders if both have partner.)

Bountiful Promenade

This land enters tapped unless you have two or more opponents.
{T}: Add {G} or {W}.

Island

Rogue's Passage

{T}: Add {C}.
{4}, {T}: Target creature can't be blocked this turn.

Reliquary Tower

You have no maximum hand size.
{T}: Add {C}.

K-9, Mark I

Negative — As long as K-9 is untapped, other legendary creatures you control have ward {1}.
Affirmative — {1}{U}, {T}: Target legendary creature can't be blocked this turn.
Doctor's companion (You can have two commanders if the other is the Doctor.)

Counterspell

Path to Exile

Exile target creature. Its controller may search their library for a basic land card, put that card onto the battlefield tapped, then shuffle.

Breeding Pool

({T}: Add {G} or {U}.)
As this land enters, you may pay 2 life. If you don't, it enters tapped.

Tireless Tracker

Landfall — Whenever a land you control enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you sacrifice a Clue, put a +1/+1 counter on this creature.