A salt could be formed by an alkali metal and what?
Lots of things form salts with alkali metals, but perhaps the best known cases are the halogens, meaning "salt formers" -- fluorine, chlorine, bromine, iodine.
Could gold be like a halogen? Not entirely, of course, but this fairly electronegative metal does form a compound with cesium whose structure resembles an alkali metal halide. See https://en.wikipedia.org/wiki/Caesium_auride.