Dropdown buttons or menu buttons, typically marked by a trailing arrow icon, are a unique button type designed to reveal a list of options or actions upon activation. They're especially useful for decluttering your interface and streamlining the user experience. Rather than presenting users with multiple individual buttons, a dropdown button neatly tucks away options, making them accessible in a single click.

This can be a real advantage when screen real estate is at a premium or when you want to offer secondary actions without overwhelming users. However, it's crucial to ensure the dropdown only contains related actions and doesn't serve as a catch-all bucket. The aim is to make users' decisions easier, not more complicated.