You can search for items in a Lists tool using Windows Search.
Note: Windows Search does not return results for content in external lists. However, external lists provide their own search facility. See Searching for items in an external list for more information.
On the Home tab, click Search.
The Search window opens, scoped to searching SharePoint Workspace.
Note: You can start a search for items by clicking Search in a workspace or in the Launchbar.
Type the text you are looking for in a Lists tool item in the Search text box.
The Search Result window lists all items that match the text you entered. Double-click an item in the Search Result to go to the item in its Lists tool.