Prowcatcher Specialist

Haste
Exhaust — {3}{R}: Put two +1/+1 counters on this creature. (Activate each exhaust ability only once.)

Pacesetter Paragon

Exhaust — {2}{R}: Put a +1/+1 counter on this creature. It gains double strike until end of turn. (Activate each exhaust ability only once.)

Return the Favor

Spree (Choose one or more additional costs.)
+ {1} — Copy target instant spell, sorcery spell, activated ability, or triggered ability. You may choose new targets for the copy.
+ {1} — Change the target of target spell or ability with a single target.

Essence Flux

Exile target creature you control, then return that card to the battlefield under its owner's control. If it's a Spirit, put a +1/+1 counter on it.

Marvin, Murderous Mimic

Marvin has all activated abilities of creatures you control that don't have the same name as this creature.

Stampeding Scurryfoot

Exhaust — {3}{G}: Put a +1/+1 counter on this creature. Create a 3/3 green Elephant creature token. (Activate each exhaust ability only once.)

Loot, the Pathfinder

Double strike, vigilance, haste
Exhaust — {G}, {T}: Add three mana of any one color. (Activate each exhaust ability only once.)
Exhaust — {U}, {T}: Draw three cards.
Exhaust — {R}, {T}: Loot deals 3 damage to any target.

Sting, the Glinting Dagger

Equipped creature gets +1/+1 and has haste.
At the beginning of each combat, untap equipped creature.
Equipped creature has first strike as long as it's blocking or blocked by a Goblin or Orc.
Equip {2}

Greasewrench Goblin

Exhaust — {2}{R}: Discard up to two cards, then draw that many cards. Put a +1/+1 counter on this creature. (Activate each exhaust ability only once.)

Redshift, Rocketeer Chief

Vigilance
{T}: Add X mana of any one color, where X is Redshift's power. Spend this mana only to activate abilities.
Exhaust — {10}{R}{G}: Put any number of permanent cards from your hand onto the battlefield. (Activate each exhaust ability only once.)

Agatha's Soul Cauldron

You may spend mana as though it were mana of any color to activate abilities of creatures you control.
Creatures you control with +1/+1 counters on them have all activated abilities of all creature cards exiled with Agatha's Soul Cauldron.
{T}: Exile target card from a graveyard. When a creature card is exiled this way, put a +1/+1 counter on target creature you control.

Rocketeer Boostbuggy

Whenever this Vehicle attacks, create a Treasure token. (It's an artifact with "{T}, Sacrifice this token: Add one mana of any color.")
Exhaust — {3}: This Vehicle becomes an artifact creature. Put a +1/+1 counter on it. (Activate each exhaust ability only once.)
Crew 1

Thassa, Deep-Dwelling

Indestructible
As long as your devotion to blue is less than five, Thassa isn't a creature.
At the beginning of your end step, exile up to one other target creature you control, then return that card to the battlefield under your control.
{3}{U}: Tap another target creature.

Unstoppable Plan

At the beginning of your end step, untap all nonland permanents you control.

Riverchurn Monument

{1}, {T}: Any number of target players each mill two cards. (Each of them puts the top two cards of their library into their graveyard.)
Exhaust — {2}{U}{U}, {T}: Any number of target players each mill cards equal to the number of cards in their graveyard. (Activate each exhaust ability only once.)

Ghostly Flicker

Exile two target artifacts, creatures, and/or lands you control, then return those cards to the battlefield under your control.

Agatha of the Vile Cauldron

Activated abilities of creatures you control cost {X} less to activate, where X is Agatha's power. This effect can't reduce the mana in that cost to less than one mana.
{4}{R}{G}: Other creatures you control get +1/+1 and gain trample and haste until end of turn.

Greenbelt Guardian

{G}: Target creature gains trample until end of turn.
Exhaust — {3}{G}: Put three +1/+1 counters on this creature. (Activate each exhaust ability only once.)

Hazard of the Dunes

Trample, reach
Exhaust — {6}{G}: Put three +1/+1 counters on this creature. (Activate each exhaust ability only once.)

Thousand-Year Elixir

You may activate abilities of creatures you control as though those creatures had haste.
{1}, {T}: Untap target creature.

Kelpie Guide

{T}: Untap another target permanent you control.
{T}: Tap target permanent. Activate only if you control eight or more lands.

Skystreak Engineer

Flying
Exhaust — {4}{U}: Put two +1/+1 counters on this creature. (Activate each exhaust ability only once.)

Training Grounds

Activated abilities of creatures you control cost {2} less to activate. This effect can't reduce the mana in that cost to less than one mana.

Rangers' Refueler

Whenever you activate an exhaust ability, draw a card.
Exhaust — {4}: This Vehicle becomes an artifact creature. Put a +1/+1 counter on it. (Activate each exhaust ability only once.)
Crew 2

Spire Mechcycle

Haste
Exhaust — Tap another untapped Mount or Vehicle you control: This Vehicle becomes an artifact creature. Put a +1/+1 counter on it for each Mount and/or Vehicle you control other than this Vehicle. (Activate each exhaust ability only once.)
Crew 2

Retreat to Coralhelm

Landfall — Whenever a land you control enters, choose one —
• You may tap or untap target creature.
• Scry 1. (Look at the top card of your library. You may put that card on the bottom.)

Pit Automaton

Defender
{T}: Add {C}{C}. Spend this mana only to activate abilities.
{2}, {T}: When you next activate an exhaust ability that isn't a mana ability this turn, copy it. You may choose new targets for the copy.

Afterburner Expert

Exhaust — {2}{G}{G}: Put two +1/+1 counters on this creature. (Activate each exhaust ability only once.)
Whenever you activate an exhaust ability, return this card from your graveyard to the battlefield.

Rings of Brighthearth

Whenever you activate an ability, if it isn't a mana ability, you may pay {2}. If you do, copy that ability. You may choose new targets for the copy.

Boommobile

When this Vehicle enters, add four mana of any one color. Spend this mana only to activate abilities.
Exhaust — {X}{2}{R}: This Vehicle deals X damage to any target. Put a +1/+1 counter on this Vehicle. (Activate each exhaust ability only once.)
Crew 2

Locus of Enlightenment

Locus of Enlightenment has each activated ability of the exiled cards used to craft it. You may activate each of those abilities only once each turn.
Whenever you activate an ability that isn't a mana ability, copy it. You may choose new targets for the copy.

The Enigma Jewel

The Enigma Jewel enters tapped.
{T}: Add {C}{C}. Spend this mana only to activate abilities.
Craft with four or more nonlands with activated abilities {8}{U} ({8}{U}, Exile this artifact, Exile the four or more from among other permanents you control and/or cards in your graveyard: Return this card transformed under its owner's control. Craft only as a sorcery.)

The Enigma Jewel // Locus of Enlightenment

Boom Scholar

Exhaust abilities of other permanents you control cost {2} less to activate.
Exhaust — {4}{R}{G}: Creatures and Vehicles you control gain trample until end of turn. Put two +1/+1 counters on this creature. (Activate each exhaust ability only once.)

Displace

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

Camera Launcher

Exhaust — {3}: Put a +1/+1 counter on this creature. Create a 1/1 colorless Thopter artifact creature token with flying. (Activate each exhaust ability only once.)

Skyserpent Seeker

Flying, deathtouch
Exhaust — {4}: Reveal cards from the top of your library until you reveal two land cards. Put those land cards onto the battlefield tapped and the rest on the bottom of your library in a random order. Put a +1/+1 counter on this creature. (Activate each exhaust ability only once.)

Sita Varma, Masked Racer

Exhaust — {X}{G}{G}{U}: Put X +1/+1 counters on Sita Varma. Then you may have the base power and toughness of each other creature you control become equal to Sita Varma's power until end of turn. (Activate each exhaust ability only once.)

Keen Buccaneer

Vigilance
Exhaust — {1}{U}: Draw a card, then discard a card. Put a +1/+1 counter on this creature. (Activate each exhaust ability only once.)

Elvish Refueler

During your turn, as long as you haven't activated an exhaust ability this turn, you may activate exhaust abilities as though they haven't been activated.
Exhaust — {1}{G}: Put a +1/+1 counter on this creature. (Activate each exhaust ability only once.)

Legolas's Quick Reflexes

Split second (As long as this spell is on the stack, players can't cast spells or activate abilities that aren't mana abilities.)
Untap target creature. Until end of turn, it gains hexproof, reach, and "Whenever this creature becomes tapped, it deals damage equal to its power to up to one target creature."

Splash Portal

Exile target creature you control, then return it to the battlefield under its owner's control. If that creature is a Bird, Frog, Otter, or Rat, draw a card.

Draconautics Engineer

Exhaust — {R}: Other creatures you control gain haste until end of turn. Put a +1/+1 counter on this creature. (Activate each exhaust ability only once.)
Exhaust — {3}{R}: Create a 4/4 red Dinosaur Dragon creature token with flying.

Deadeye Navigator

Soulbond (You may pair this creature with another unpaired creature when either enters. They remain paired for as long as you control both of them.)
As long as Deadeye Navigator is paired with another creature, each of those creatures has "{1}{U}: Exile this creature, then return it to the battlefield under your control."

Sabotage Strategist

Flying, vigilance
Whenever one or more creatures attack you, those creatures get -1/-0 until end of turn.
Exhaust — {5}{U}{U}: Put three +1/+1 counters on this creature. (Activate each exhaust ability only once.)

Lilysplash Mentor

Reach
{1}{G}{U}: Exile another target creature you control, then return it to the battlefield under its owner's control with a +1/+1 counter on it. Activate only as a sorcery.

Mindspring Merfolk

Exhaust — {X}{U}{U}, {T}: Draw X cards. Put a +1/+1 counter on each Merfolk creature you control. (Activate each exhaust ability only once.)

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.

Teferi's Time Twist

Exile target permanent you control. Return that card to the battlefield under its owner's control at the beginning of the next end step. If it enters as a creature, it enters with an additional +1/+1 counter on it.