Come to think of/about it, there are several other phrases that can be used to express the same idea. One alternative is "now that you mention it," which acknowledges the trigger for prompting the thought. Another possible phrase is "upon reflection," which suggests a more deliberate and thoughtful consideration. "In retrospect" also conveys a sense of hindsight or looking back on something. Alternatively, "it occurs to me" implies a sudden realization or epiphany. Regardless of the phrase used, all convey the idea of reconsidering a thought or idea in a different light, often leading to new insights or perspectives.