"What all" is a colloquial phrase used to inquire about the comprehensive content or entirety of something. However, there are various synonyms available that can be employed to convey a similar meaning. Phrases such as "the entirety of", "the whole of", "everything that", and "all that" can be used interchangeably with "what all". These alternatives are especially useful in formal contexts or academic writing, where a more precise and concise language is expected. It is important to note that the choice of synonym may vary depending on the specific context and desired level of formality, but these options can assist in diversifying one's vocabulary while maintaining clarity in communication.