The phrase "my humble self" is often used to refer to oneself in a humble or modest manner. However, there are several synonyms that can be used in its place. One such alternative is "yours truly" which is a more formal and polite expression. Another option could be "the undersigned" which has a legal connotation and usually used in formal documents. "The author" or "the speaker" could also be employed depending on the context, such as in a written or oral presentation. Lastly, "this unworthy person" can be used to convey humility while addressing oneself in a more self-deprecating manner.