You can search for text with attributes that are applied either by direct formatting or by styles. For example, if you search for the Font attribute, all instances of text that do not use the default font are found. All text that has a directly coded font attribute, and all text where a style switches the font attribute, are found.
If you want to find text with any font by name, click the Format button in the Find & Replace dialog of LibreOffice Writer.
After you select the attributes that you want to search for, the Paragraph Styles box in the Other options area of the LibreOffice Writer Find & Replace dialog changes to Including Styles.
If you want to search for text in which attributes were set by using direct formatting and styles, select the Including Styles box.
The search criteria for attributes are listed below the Find box.
Choose Edit - Find & Replace.
Clear the Find text box if necessary.
In the Attributes dialog, select the Font check box, and click OK.
In the Find & Replace dialog, you now can read "Font" below the Find text box.
Click Find Next.
All places where a font change was applied, either directly or by assigning an appropriate style, are found.
To stop searching for the current attributes, reset the Find & Replace dialog to normal mode.
Click No Format.
Searching for attributes is available in the Find & Replace dialog for text documents.