The Chase Is On

Target creature gets +3/+0 and gains first strike until end of turn. Investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Red Herring

Haste
This creature attacks each combat if able.
{2}, Sacrifice this creature: Draw a card.

Forest

Crowd-Control Warden

As this creature enters or is turned face up, put X +1/+1 counters on it, where X is the number of other creatures you control.
Disguise {3}{G/W}{G/W} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)

Riftburst Hellion

Reach
Disguise {4}{R/G}{R/G} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)

Tunnel Tipster

At the beginning of your end step, if a face-down creature entered the battlefield under your control this turn, put a +1/+1 counter on this creature.
{T}: Add {G}.

Mountain

Rubblebelt Maverick

When this creature enters, surveil 2. (Look at the top two cards of your library, then put any number of them into your graveyard and the rest on top of your library in any order.)
{G}, Exile this card from your graveyard: Put a +1/+1 counter on target creature. Activate only as a sorcery.

Culvert Ambusher

When this creature enters or is turned face up, target creature blocks this turn if able.
Disguise {4}{G} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)

Vengeful Creeper

Disguise {5}{G} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)
When this creature is turned face up, destroy target artifact or enchantment an opponent controls.

Rubblebelt Braggart

Whenever this creature attacks, if it's not suspected, you may suspect it. (A suspected creature has menace and can't block.)

Hide in Plain Sight

Look at the top five cards of your library, cloak two of them, and put the rest on the bottom of your library in a random order. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)

Goblin Maskmaker

Whenever this creature attacks, face-down spells you cast this turn cost {1} less to cast.

Break Out

Look at the top six cards of your library. You may reveal a creature card from among them. If that card has mana value 2 or less, you may put it onto the battlefield and it gains haste until end of turn. If you didn't put the revealed card onto the battlefield this way, put it into your hand. Put the rest on the bottom of your library in a random order.

Connecting the Dots

Whenever a creature you control attacks, exile the top card of your library face down. (You can't look at it.)
{1}{R}, Discard your hand, Sacrifice this enchantment: Put all cards exiled with this enchantment into their owners' hands.

Cornered Crook

When this creature enters, you may sacrifice an artifact. When you do, this creature deals 3 damage to any target.

Innocent Bystander

Whenever this creature is dealt 3 or more damage, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")

Undercover Crocodelf

Whenever this creature deals combat damage to a player, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Disguise {3}{G/U}{G/U} (You may cast this card face down for {3} as a 2/2 creature with ward {2}. Turn it face up any time for its disguise cost.)

Loxodon Eavesdropper

When this creature enters, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
Whenever you draw your second card each turn, this creature gets +1/+1 and gains vigilance until end of turn.

Expose the Culprit

Choose one or both —
• Turn target face-down creature face up.
• Exile any number of face-up creatures you control with disguise in a face-down pile, shuffle that pile, then cloak them. (To cloak a card, put it onto the battlefield face down as a 2/2 creature with ward {2}. Turn it face up any time for its mana cost if it's a creature card.)

Fanatical Strength

Target creature gets +3/+3 and gains trample until end of turn.

Topiary Panther

Trample
Basic landcycling {1}{G} ({1}{G}, Discard this card: Search your library for a basic land card, reveal it, put it into your hand, then shuffle.)

Vitu-Ghazi Inspector

As an additional cost to cast this spell, you may collect evidence 6. (Exile cards with total mana value 6 or greater from your graveyard.)
Reach
When this creature enters, if evidence was collected, put a +1/+1 counter on target creature and you gain 2 life.