When looking for a "quality sample," there are a variety of synonyms you can use to find the best possible example of what you're looking for. One option is to search for a "high-quality sample," which emphasizes the level of excellence you're aiming for. Another option is "representative sample," which suggests that the sample you're seeking accurately represents a larger population. You could also use "exemplary sample," which carries connotations of being a standout or model example. If you're specifically looking for a sample that is free of errors or anomalies, "clean sample" or "flawless sample" might be appropriate descriptors.