The phrase "thinking of" is a commonly used expression to indicate that someone is considering or pondering about something. However, there are several other alternatives that can be used interchangeably based on the context of the sentence. Some of the synonyms for "thinking of" include "contemplating," "reflecting on," "musing about," "pondering," and "meditating on." Each of these synonyms conveys a slightly different meaning and can be used to express different levels of intensity or depth of thinking. Using a variety of words to express the same idea can add variety and complexity to one's writing or speech.