Let's be frank: one of the groups that gets the biggest enjoyment out of 1000 Blank White Cards is the the party of game design nerds. Specifically, game design nerds who play other card games. And one of the most common themes of CCGs is monsters. Hence, the Monster Card.
The Monster Card, at its most basic, is a card that represents some sort of entity that fights for a player. Sometimes, they protect the player themself from being attacked, othertimes they are the main target. Common elements of Monster Cards vary between most commercial card games, and as a result there is no basic template for a Monster Card. However, certain elements are common enough that they can be expected to show up at some point:
- A Name and a Picture: At least, they had better, or you're gonna have some boring fights.
- Power/Strength/Attack Value: This is how much damage the monster can inflict when it attacks.
- Hit Points/Toughness/Defense Value: This is how much damage the monster can withstand before it keels over, usually being discarded as a result. This value's exact effects can vary; sometimes it acts like health in a video game, being worn down gradually until it is reduced to zero. Othertimes, it represents how much damage must be inflicted with one attack to be effective (such as in Yu-gi-Oh!). This is more of a spectrum than two values; monsters in Magic: The Gathering must be hit with a certain amount of attack before the opponent's turn ends to be killed. Getting even more complicated, sometimes this can be split into two stats, with a health value that is depleted and a defense value that lessens the brunt of incoming attacks. The Defense can even be specialized to resist certain kinds of attacks, but that's getting a little overwhelming...
- Speed/Agility Value: While it doesn't always show up, due to the turn based nature of most card games, some battle systems require a speed stat to determine which monster attacks first. Can sometimes manifest in the form of Counter Cards, which take priority over normal cards and can interrupt their play. And of course, you can have Counter-Counter Cards, and Counter-Counter-Counter Cards...
- Cost: Some systems can require resources to summon a monster, or to have the monster attack, defend, or use a special ability. Used to balance powerful cards by making them consume more resources.
- Affinity/Element: Many card games assign affinities to monsters, such as Fire, Water, Light, Darkness, etc. Mostly these elements fall into a Rock-Paper-Scissors relationship, whether with increased/decreased effectiveness of attacks (such as in the Pokemon TCG), differing strategies with a pecking order (Magic again), or sometimes just as a category (Yu-gi-Oh! once more).
- Special Abilities: This is where it gets interesting. You can have monsters that ignore Defense, discard a card every other turn, slowly charge up their attack values, counterattack, or even cause the opponent to dance around when attacked. Commercial CCGs tend to only have monsters with balanced, game-related abilities, but you're certainly not required to follow their lead...