"Good for one" is a phrase that refers to something that benefits a single individual. There are many synonyms for this phrase, including advantageous, helpful, beneficial, useful, profitable, gainful, and expedient. While each of these words have slightly different connotations, they all share the idea of providing an advantage or benefit to a single person. Whether it's a job opportunity that's advantageous for one person, or a financial investment that's profitable for another, all of these words convey the idea that whatever it is, it works in favor of an individual. Choosing the right synonym for "good for one" depends on the context of the situation, but they all express the same idea of benefiting a single person.