Formal:
* Atenciosamente: This is the most common and formal way to end a letter or email. It literally translates to "attentively," but it's used as a polite way to express warm regards.
* Cumprimentos cordiais: This translates to "cordial greetings" and is a slightly more formal option than "Atenciosamente."
Informal:
* Abraços: This is a more informal way to say "warm regards" and literally translates to "hugs." It's appropriate for friends and family.
* Com carinho: This translates to "with love" and is a very affectionate way to end a letter or email.
* Saudações: This is a general greeting that can be used in both formal and informal contexts.
Other options:
* Melhores cumprimentos: This translates to "best regards" and is a good option for someone you know well but not intimately.
* Cordiais saudações: This translates to "cordial greetings" and is a good option for someone you're trying to be polite to.
The best choice for you will depend on the context of your communication.