Like many people here, I love fantasy and adventure. With Dominaria's recent release with the Historic mechanic that proves that "batching" is successful, I bring you a new mechanic idea, "Adventuring Party"! 

I always found it odd that often times to play Magic: The Gathering correctly, you need to focus on only one class or race of creature. However, many popular media doesn't work this way. Imagine if the Fellowship of the Ring were just hobbits. Even in the Magic: The Gathering story, the main cast is all varied in powers, class, and abilities. 

This is what Adventuring Party seeks to remedy! 

Like the new(ish) Historic mechanic, Adventuring Party uses the "batching" method.

For the unaware, Historic is a mechanic that looks for a specific subset of cards. For Historic, it's Artifact, Legendary, and Sagas.  

Would you like to join our Discord community of tabletop gamers to discuss mechanics, game design, anime, and more?!

So, what's Adventuring Party? It's a batching mechanic that checks for three creatures each with at least one creature type, "Warrior, Wizard, and Rogue." Once you have all three, it will give you a special bonus. 

Dungeon Lurker 1B
Human Rogue - Common
As long as you control an adventuring party, creatures you control gain deathtouch. (You have an adventuring party when you control at least three creatures and the following creature types: Warrior, Wizard, and Rogue.)
2/2

This mechanic gives us the cool flavor of forming an adventuring party to fight dangerous enemies with! It also provides a unique deckbuilding challenge to include enough creatures of three different tribes and having the right amount of each one.

Airborne Sniper 3G
Elf Rogue - Common
Reach
As long as you control an adventuring party, creatures you control gain reach.
2/3

Lightblade Skirmisher 1W
Human Warrior - Common
As long as you control an adventuring party, creatures you control gain lifelink.
2/2

Many of the commons and uncommons would be designed with a similar template as these to make this new mechanic easier to understand easily upon first reading. It also achieves the feeling of your creatures helping others out in their party.

If you wish to read a lot more of my card ideas using Adventuring Party, or would be fun tools such as Artifacts and Lands that would work well with them, then look no further! 

Rynas, the Fireblade 3RW
Legendary Creature - Human Warrior Wizard (Rare) 
Double Strike
As long as you control an adventuring party, creatures you control gain double strike.
3/4

Hazagan, the Stormbright 2URW
Legendary Creature: Human Wizard (Rare) 
As long as you control an adventuring party, creatures you control have, “whenever this creature attacks, it deals damage equal to its power to target player.”
1/7

Out of the Dungeon 2B
Sorcery (Common)
Return from your graveyard up to one warrior, one wizard, and one rogue to your hand.
“We thought they wouldn't make it, but alas, the heroes emerged!”

Adventures Tavern – Land (Rare)
T: Add <> to your mana pool.
T: Add one mana of any color to your mana pool. This mana may only be spent to cast a Warrior, Wizard, or Rogue creature spell.

Vitality Vigor – 1
Artifact (Common)
1(T): Sacrifice Vitality Vigor, draw a card.
3(T): Sacrifice Vitality Vigor, target creature gains indestructible until the end of turn.

Blessed Summoner – 1G
Creature: Elf Wizard (Rare)
T: Add one mana of any color to your mana pool. Spend this mana only to cast a warrior, wizard, or rogue creature spell.
1/3

Kyln, the Hero - BUR
Creature: Human Warrior Wizard Rogue (Rare)
Whenever Kyln, the Hero enters the battlefield, create a 1/1 Warrior, Wizard, and Rogue token. 3/3
“Those that accompany Kyln don't get much experience in the dungeon, but they do feel safe.”

It's Dangerous To Go Alone (3)
Sorcery

You may spend any color mana to cast this spell. Then apply the effect for each instance you used that color mana.

• Green/White: Create a 1/1 warrior.

• Blue/Red: Create a 1/1 wizard.

• Black: Create a 1/1 rogue.

Opportune Backstabber 2UB
Creature: Elf Rogue (Uncommon) 
This creature gains deathtouch and prowess as long as you control a warrior.
1/4

Strategic Skirmisher 2WG
Creature: Elf Rogue (Uncommon)
This creature gains trample and lifelink as long as you control a wizard.
2/3

Stormdancer 1UR
Creature: Human Wizard (Uncommon)
This creature has flying and haste as long as you control a rogue.
2/1

Borgaz, Hulking Support 5B
Legendary Creature: Giant Warrior (Uncommon)
Whenever Borgaz attacks, you may return a wizard, warrior, or rogue, from your graveyard to your hand.
5/5