The phrase "goose laid the golden egg" is often used to refer to something that is highly valuable or profitable. However, there are a number of synonyms that can be used to convey a similar meaning. Some possible synonyms include "cash cow," "meal ticket," "holy grail," and "pot of gold." Other options might include "golden opportunity," "cash machine," "treasure trove," or "pearl of great price." Regardless of the specific term used, the idea is that there is something of great value that must be preserved or protected in order to continue reaping benefits from it in the future.