Reference Viewer is a very useful editor plugin for Unity. It allows the user to quickly and easily view all references to a selected object, whether it be in the gameplay scene or in the project's asset database.
Unity heavily relies on objects referencing other objects, but no easy functionality is built in to get an overview of those references inside the editor. This tool attempts to solve that problem by visually presenting a list of objects whose serialized properties contain a reference to the selected object. This plugin is built right into the editor's context menus and requires no additional setup to work. You can click on a found reference to immediately jump to it in the scene or asset browser.
This plugin is available on the Unity Asset Store here.