Guidance Out Of Darkness Act or the GOOD Act (Sec. 3) This bill requires an agency to: (1) publish guidance documents online on the dates they are issued, (2) publish all of its guidance documents that are in effect in a single location on an online portal designated by the Office of Management and Budget (OMB), and (3) display a hyperlink on the agency's online portal that provides access to the guidance documents. The documents must be identified as guidance documents, sorted into subcategories, published in a machine-readable and open format, and searchable. On the date a guidance document is rescinded, an agency must add an indication on the online portal designated by OMB that the guidance document is rescinded and the date on which it was rescinded. OMB must designate an online portal within 30 days.