Card Game Character Concepts

[fizzybobnewt]

***An Short Summary of the Situation***
Basically, I need help coming up with a basic situation/setting concept for my card game, from which to derive card ideas. If that sounds interesting, please read on.

***A True Story***
Long ago, in the Milky Way, maybe like 3rd grade, I saw an episode of Yu-Gi-Oh in which Yugi's opponent flooded the room in-game, with some sort of water-related card. Which meant Yugi was able to use an electric-themed attack which was conducted through the water to zapperate all of the enemy cards. I was pretty sure this would never work in Yu-Gi-Oh, so I set out to make a card game in which it would.
Here we are years later. I found the old cards I'd made, polished up the concept a whole bunch, and set out making new cards.

***An Attempt To Explain My Game***
Cards have abilities that may affect certain subtypes; some effects add or remove subtypes on cards.
Examples: Rainbow Dash is a Pony, a Winged Creature, Rainbow-Themed, Female, and so on. Voldemort is Dark-Themed, a Magic-User, a Parselmouth, etc.
Cards don't have a list of all their subtypes—some are specified, and most are obvious. But as I said, abilities affect spcertain subtypes: Electric Bug, for instance, specifies that it does extra damage to Wet creatures. And Summon Bigger Fish grants you another, more powerful copy of any Aquatic creature.

***The Heart of the Problem***
Due to the gameplay style, nearly all the cards are references and characters from other people's creations, from webcomics to video games to Dr. Seuss books. It's not that I'm uncreative, just that with a game like this, where abilities aren't so much boiled down into numbers as with other games, it's hard to come up with a cast of interesting, diverse creatures without just making up meaningless names and assigning powers at random. It works well to grab already-invented characters from all forms of media, because the basic premises of their stories are so different from each other, but even aside from copyright issues, a game entirely of references is not the feel I'm going for here.
I need a place to start: some general, underlying theme that I can work from to make cards. But if it's too specific, all the cards end up with more-or-less the same subtypes, and then they're just slinging numbers at each other.

***A Final Note About the Game***
It's called Death Game, because I'm trying to lampshade the fact that so many card games are just two enormous armies of fantastical creatures hacking each other to bits.

***Some Examples of Cards***
In case it helps you understand the game:

Spoiler

Show

X=Discard this card to...
*#=Do this much damage.
@=Flavor text
€=Effect card (cannot play it to the field.)
(#/#)=Atk/Def
¥=Equip card.
₩ = creature with this card equipped...

Subtypes will be further clarified when the cards have pictures.

•Combustible Lemons
X: Target creature gains 5 life.
*5 when thrown.
@Get mad!

•Valve
X: If something would get wet, it doesn't. Works only in the moment it's discarded.
While Valve is in play, playing Portal, Portal 2, Crowbar, or Turret does not count as*playing a card.
@As a necessity, there can can only ever be two copies of this card. Never three.

•Crowbar ¥
₩ may do *5 in addition to their normal attack.
*7 when thrown.
@Be a Free man.

•That 1 Guy (0/3)
A musician. May have any number of items equipped at once.
While That 1 Guy is in play, playing Laser Beans or The Void does not count as playing a card.
@Look up to the moon... whistle up a tune... keep it to yourself for now, this ain't no lie.

•Weed Whacker ¥
₩ may do *5 in addition to their normal attack. Instead, they may choose to destroy a plant.
@I hear youse needs some weed fella "disappeared"?

•Carlisle (9/10)
A doctor who is also a vampire.
If Carlisle kills a creature, you may instead choose to "turn" it, giving it +5/+6 and the Vampire subtype, and putting it under your control.
Instead of attacking, Carlisle may choose to throw an object.
@Don't worry, he is strictly a vegetarian.

•Dr. McNinja (8/6)
A doctor who is also a ninja.
If you also have Judy, she and Dr. McNinja can attack together, combining Atk and Def.
@Yes, I'm a ninja, and Judy's a gorilla. Can't you see we're people too?

•Somebody Else's Problem Field ¥
SEP Field does not take effect until a subtype of ₩ has been altered or added while SEP Field is equipped. Once in effect, ₩ cannot be attacked or, in fact, have anything done to him for 5 turns. After those 5, discard this.
@Eh, don't worry about it. Someone else can kill him.

•Internal Badgers €
Target creature dies in 3 turns, unless they experience a "remove poison" sort of effect. After those 3 turns, you gain 3 4/3 Badger creatures.
@Based on a true story.

•Matchstick Girl (3/5)
Heavily inflammable.
@Please, I don't like open flames.

•The Cat (7/3)
If The Cat gets wet, it has -5 to Atk.
@I will lie on your newspaper and scratch your curtains. I will walk incredibly slowly, right in front of you. Look how cute I am. Now you will pet me.