If something goes off the chart, it far exceeds the normal standards, good or bad, for something.
Uncharted waters
If you're in uncharted waters, you are in a situation that is unfamiliar to you, that you have no experience of and don't know what might happen. ('Unchartered waters' is an incorrect form that is a common mistake.)
An chart idiom dictionary is a great resource for writers, students, and anyone looking to expand their vocabulary. It contains a list of words with similar meanings with chart, allowing users to choose the best word for their specific context.
Dicionário de palavras semelhantes, Diferentes palavras, Sinônimos, Expressões idiomáticas para Idioma chart