The largest importer of saffron in the world is Fernet Branca®. This bitter, not very common in cocktails, is not to confuse with regular bitters of which you use a couple of dashes to add flavor.
Scotch Whisky, Campari, Fernet Branca
Gin, Orange Flavored Brandy, Dubonnet, Fernet Branca
Cognac, Fernet Branca, Simple Syrup, Bitters, Orange
Bourbon, Fernet Branca, Vermouth, Sweet