There are several synonyms for the phrase "toots one's horn" that can be used for more variety in writing and speech. "Brags," "boasts," and "shows off" all convey a sense of someone talking highly of themselves. "Praises oneself" or "speaks highly of oneself" are more formal ways to express the same idea. "Touts" may also be used to suggest promoting oneself or one's achievements. Finally, "blows one's own trumpet" and "pats oneself on the back" are unique ways to describe someone who is displaying self-aggrandizement, and could add colorful language to any writing or speaking task.