The phrase "but good" is often used colloquially to intensify a description or action. However, there are several synonyms that can be used to convey a similar meaning. "Exceptionally" and "remarkably" both emphasize the exceptional quality of something. "Exceedingly" and "extraordinarily" also convey a sense of something being beyond normal expectations. "Incredibly" and "unbelievably" are more informal synonyms that can be used to express surprise or amazement at a situation. Finally, "heartily" and "vigorously" convey a sense of enthusiasm and wholeheartedness in an action. All of these synonyms can be used in place of "but good" to add emphasis to a statement or description.