As disparate an assortment as singers of the New York Metropolitan Opera and O'Flaherty's pub in New Orleans swear by slippery elm tea, available commercially in U.S. as "Throat Coat" teabags, somewhat licorice-like taste, goes well with honey and very soothing if you are "scratchy." Singers east of the Pond seem to go for the blackcurrant tea, and Lemsip.
Alcohol is not bad as a pain soother, but is dehydrating; exactly what you do not want to do to healing vocal cords. Caffeine also best avoided.
Celtaddict (MD, in Mommy Moment)