At all is a common phrase used to indicate the extent of something. It is often used in negative sentences or questions to emphasize that the speaker is not familiar with or is completely unfamiliar with the subject matter. Synonyms for at all include words such as whatsoever, in the slightest degree, in the least degree, in the slightest manner, and in the least manner. These synonyms could be used to add variety and nuance to a sentence rather than using the same phrase repeatedly. It is essential to use the correct synonym in the appropriate context to ensure that the message is conveyed accurately.