Votes: netn10, Rithaniel

Rakdos Rave 1BR
Sorcery (R)
Creatures get +2/-2 until end of turn.
Creatures you control gain menace until end of turn.

IIW: Murder mystery

Votes: Sporegorger_Dragon, Subject16

Catalytic Crawler R
Creature - Salamander (C)
Sacrifice Catalytic Crawler: Add R. When this mana is spent on a red spell or ability that deals damage, that spell or ability deals one additional damage.
1/1

Inscrutable Shuffler 2C
Creature - Eldrazi Drone (C)
Inscrutable Shuffler can't be blocked as long as you have unspent colorless mana.
2/3
The movements of the Eldrazi are unconstrained by petty notions such as space.

Votes: Raptorchan, void_nothing

Preserver of Destinies 1U
Creature - Vedalken Wizard (U)
When Preserver of Destinies enters the battlefield, Scry 2.
Whenever you would shuffle, you may exile the top card of your library face-down, shuffle, and then put that card on top of your library.
1/3

Votes: Rithaniel, Raptorchan (I have no idea how this is supposed to work, but I really want to see it made to work!)

Vigean Protector 3GU
Creature - Angel Mutant
Flying, Ward 2
2/4
"The wings? Nah, that's easy. It's the halo that's the hard part."

IIW: Three-color kicker

Votes: bravelion83, void_nothing The Founding of Simic 1GU Enchantment - Saga (R) Speed read 3 (You may pay an additional 3 as you cast this spell. If you do, trigger all 3 chapters, letting each chapter fully resolve before triggering the next chapter. Then sacrifice this Saga.) I: Put a +1/+1 coun...

Votes: Raptorchan, void_nothing

Royal Kennelmaster 1R
Creature - Human Noble (R)
Dogs you control get +1/+1.
2/2
////
Release the Hounds XXR
Sorcery - Adventure
Create X+1 1/1 red Dog creature tokens. Those creatures gain haste until end of turn.

IIW: Dance party

I went with "Card that captures a really annoying thing from real life"

Ophidian Steed 1UG
Creature - Snake Horse

Votes: netn10, Rithaniel

Stoke Ferocity X{R/G}
Sorcery (R)
Target creature gains trample until end of turn. If R was spent to cast this spell, that creature gets +X/+0 until end of turn. If G was spent to cast this spell, that creature gets +X/+X until end of turn.

Votes: Frostboss216, Rithaniel

Unexpected Item in Battle Area W
Instant (U)
Buyback 3
Target player removes a creature they control from combat.

IIW: Bears

Maybe the first ability could use mana value "up to X+1"? That makes it quite different (now you can cycle between two creatures with ETB effects), but maybe that would play better. You do that, and any two untappers creates an infinite loop of death and rebirth. Maybe change it to X+1 or...

Votes: netn10, emily

Dig in Spurs - R
Instant (C)
Target creature gets +1/+1 and gains haste until end of turn. If it is a Knight or Cowboy, it gains trample until end of turn and you draw a card.

Shark Fin 1
Artifact - Equipment
Equipped creature gets +1/+0 and may block creatures with islandwalk as if they did not have islandwalk.
Equip 1

Jaws and Paws 3GU
Creature - Shark Bear
Trample
Evolve
2, Remove a +1/+1 counter from Jaws and Paws: Jaws and Paws fights target creature.
4/3

Apes! Apes! + Mirror Mirror

Monkey Monkey 3UG
Enchantment
Whenever a non-Monkey creature enters the battlefield, its controller chooses one of their opponents. That player creates a creature token that is a copy of that creature except that it is a green Monkey.

Loxodon Reveler BRG Creature — Elephant Berserker (R) Madness—Pay 4 life. Trample When Loxodon Reveler enters the battlefield, each player discards a card. After a century of boring Selesnya rites, some young loxodon find the need to stretch their legs and party. 4/4 IIW: Full throttle I really lik...

Votes: netn10, Rithaniel

Recess 2R
Sorcery (R)
Untap all creatures you control with mana value 3 or less. After this main phase, there is an additional combat phase followed by an additional main phase.

IIW: Murder Mystery

Looking good! I'll aim to judge tomorrow late morning.

Votes: netn10, Raptorchan

Run Out of Town 1W
Instant (U)
Cast this spell only during combat.
Exile target creature with toughness less than or equal to the number of attacking creatures you controlled as you cast this spell.

Votes: KB52665, Rithaniel

Boggart Beatdown XXR
Sorcery (R)
Boggart Beatdown deals damage equal to the number of Goblins you control to X target creatures.

IIW: Bestow

Thanks!

Now everyone, show me your guild-mashups, your oops-this-guild-got-stuck-on-that-plane, etc etc

Electric Fence 1RR Artifact Creature - Wall Defender When Electric Fence enters the battlefield, create a Generator artifact token. Electric Fence gets +5/+0 as long as you control a Generator. Dinosaurs your opponents control have " T : Destroy target Generator." 1/3 Next: A technologica...

Votes: Raptorchan, RattingRots

Stinging Accusation 1B
Instant (C)
Investigate. Then target creature gets -X/-X until end of turn, where X is the number of Clues you control.

Votes: netn10, LandellXil0cent Bohemian Rhapsody (Part 1) UR Enchantment - Saga (R) (i) Is this the real life? Is this just fantasy? -- Exile target creature you control, then return it to the battlefield. (ii) Caught in a landslide, no escape from reality... -- Bohemian Rhapsody deals 2 damage to u...

Kjeldoran Barracks
Land (R)
Kjeldoran Barracks enters the battlefield tapped.
T: Add W.
Outlast 1
1W: Kjeldoran Barracks becomes a 1/1 white Soldier creature until end of turn. It's still a land.