Nothing

NO LIGHTS means follow the path of basic primary power

From battery.........to starter relay "big stud"--through FUSE LINK----through BULKEAD CONNECTOR (RED) to ammeter---out ammeter on big black--------to under dash welded splice--------branch off-------

feeds headlights power
feeds fuse box "hot" buss (stoplights, etc)
feeds power to IGNITION SWITCH

So your main big "usual suspects"

are fuse link, bulkhead connector, ammeter problems, or the welded splice, which is rare but does happen.