Bartender is a long-running indie macOS utility that gives you total control over the menu bar. You can hide individual icons, rearrange their order, group them into a secondary bar that reveals on hover or hotkey, and have them auto-appear when the underlying app needs your attention. It is one of the canonical "essential Mac apps" recommended on basically every macOS power-user list.

The app is paid (one-time license per major version, currently Bartender 6), with a free trial. It is developed by Surtees Studios, a small UK-based studio, and has been continuously updated since 2012. Each major macOS release that changes the menu-bar internals usually ships with a corresponding Bartender update to keep up.