12. (15 points) There are 20 cards, each with a natural number greater than 0 written on it, and the sum of the natural numbers on any 9 cards does not exceed 63. If a card with a natural number greater than 7 is called a "Dragon Card," how many "Dragon Cards" can there be at most among these 20 cards? What is the maximum possible sum of the natural numbers on all "Dragon Cards"?
【Analysis】Since the smallest number written on a "Dragon Card" is $8, 8 \times 8 = 64 > 63$, there can be at most 7 cards; Let the sum of the natural numbers written on 7 "Dragon Cards" be $S$. If we add two more cards with numbers less than 8, we will have 9 cards. When the sum of these two cards is the smallest, the value of $S$ is the largest. Since each card has a natural number greater than 0, the smallest number is 1, so when these two cards are both 1, their sum is the smallest, which is 2. Since the sum of the natural numbers on any 9 cards does not exceed 63, the maximum value is 63, so the maximum value of $S$ is: $63 - 2 = 61$; according to this, solve.

【Solution】Solution: Since the smallest number written on a "Dragon Card" is $8, 8 \times 8 = 64 > 63$, 8 cards do not meet the requirement, so there can be at most 7 cards; the remaining 13 cards are all cards with numbers less than 8;

Let the sum of the natural numbers written on 7 "Dragon Cards" be $S$. If we add two more cards with numbers less than 8, we will have 9 cards. When the sum of these two cards is the smallest, the value of $S$ is the largest,

Since each card has a natural number greater than 0, the smallest number is 1, so when these two cards are both 1, their sum is the smallest, which is 2,

Since, the sum of the natural numbers on any 9 cards does not exceed 63, the maximum value is 63,
So the maximum value of $S$ is: $63 - 2 = 61$;
Answer: Among these 20 cards, the maximum number of "Dragon Cards" is 7, and the maximum sum of the natural numbers written on all "Dragon Cards" is 61.