Dimir Strandcatcher

Flying
Whenever you attack, surveil X, where X is the number of opponents being attacked.
At the beginning of each end step, if three or more cards were put into your graveyard from anywhere other than the battlefield this turn, draw a card.

Ecstatic Electromancer

Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.)
Whenever this creature enters or attacks, you may discard a card. If you do, draw a card.

Frenzied Gorespawn

When this creature enters, for each opponent, goad target creature that player controls. (Until your next turn, those creatures attack each combat if able and attack a player other than you if able.)
Whenever one or more creatures attack one of your opponents, those creatures gain menace until end of turn.

Furious Spinesplitter

Trample
At the beginning of your end step, put a +1/+1 counter on this creature for each opponent who was dealt damage this turn.

Herald of Ilharg

Trample
Whenever you cast a creature spell, put two +1/+1 counters on this creature. If that spell has mana value 5 or greater, this creature deals damage equal to the number of counters on it to each opponent.

Incriminating Impetus

Enchant creature
When this Aura enters, suspect enchanted creature. (It has menace and can't block.)
Enchanted creature gets +2/+2 and is goaded. (It attacks each combat if able and attacks a player other than you if able.)

Clue

Lavinia, Foil to Conspiracy

Vigilance
Whenever you cast your second spell each turn, investigate. (Create a Clue token. It's an artifact with "{2}, Sacrifice this token: Draw a card.")
{T}: Add {C}{C}. Activate only during an opponent's turn.

Lonis, Genetics Expert

Evolve (Whenever a creature you control enters, if that creature has greater power or toughness than this creature, put a +1/+1 counter on this creature.)
Whenever one or more +1/+1 counters are put on Lonis, investigate that many times.
Whenever you sacrifice a Clue, put a +1/+1 counter on another target creature you control.

Memory Vampire

Flying
Whenever this creature deals combat damage to a player, any number of target players each mill that many cards. Then you may collect evidence 9. When you do, you may cast target nonland card from defending player's graveyard without paying its mana cost.

Ordruun Mentor

Mentor (Whenever this creature attacks, put a +1/+1 counter on target attacking creature with lesser power.)
Whenever you attack a player, target creature that's attacking that player gains first strike until end of turn.

Headliner Scarlett

Haste
When Headliner Scarlett enters, creatures target player controls can't block this turn.
At the beginning of your upkeep, exile the top card of your library face down. You may look at and play that card this turn.

Portal Manipulator

Flash
When this creature enters during the declare attackers step, choose target player and any number of target attacking creatures their opponents control. Those creatures are now attacking that player.

Resonance Technician

Flying
When this creature enters, you may discard a card. If you do, investigate twice.
{T}, Tap X untapped artifacts you control: Copy target instant or sorcery spell you control with mana value X. You may choose new targets for the copy.

Scuttling Sentinel

Flash
Vigilance
When this creature enters, put a +1/+1 counter on another target creature you control. Until end of turn, that creature becomes a blue Crab in addition to its other types and gains hexproof. (It can't be the target of spells or abilities your opponents control.)

Sludge Titan

Trample
Whenever this creature enters or attacks, mill five cards. You may put a creature card and/or a land card from among them into your hand.

Boar

Stampede Surfer

Haste
Whenever this creature attacks, for each opponent, you create a 2/2 green Boar creature token that's tapped and attacking that opponent.

Ravnica: Clue Edition