David is a name that is suitable for many types of short stories. It has a timeless quality. In a short story about family, David could be the eldest son who has to take on a lot of responsibilities when his father falls ill. He learns about love, sacrifice and growing up in the process.
Sure. One is Sam. Sam is a common name that works well in short stories. It can be easily associated with different personalities. For instance, Sam could be a shy boy in a story about school life, trying to overcome his shyness.