If you're looking for synonyms for the phrase "be as cute as a button," there are plenty of options to choose from. You could say someone is "adorable," "charming," "endearing," or "winsome." Other options might include "sweet," "lovely," "precious," "delightful," or "irresistible." Some alternatives might focus on a particular aspect of cuteness, such as "cuddly," "fluffy," "fuzzy," or "squeezable." Whatever word you choose, the sentiment will be clear: you think the person or object in question is absolutely delightful and appeals to your sense of cuteness and charm.