The question is a little vague.
Rust is iron oxide. You would need iron and oxygen to form iron oxide. Adding salt to water (sodium chloride ions) causes some of the hydrogen and oxygen in water to form hydrogen and oxygen ions. This increases the number of oxygen ions (compared to water) and the oxygen ions react with the iron to form rust. Anything that brings oxygen into contact with iron will accelerate the reaction. Any oxygen rich compound that can be dissolved in a solvent with iron will work. Think of ammonium sulfate in water. Sodium Hyroxide in water. Carbonic acid. Oxygen gas. A higher temperature also increases the reaction rate.
Rust is iron oxide. You would need iron and oxygen to form iron oxide. Adding salt to water (sodium chloride ions) causes some of the hydrogen and oxygen in water to form hydrogen and oxygen ions. This increases the number of oxygen ions (compared to water) and the oxygen ions react with the iron to form rust. Anything that brings oxygen into contact with iron will accelerate the reaction. Any oxygen rich compound that can be dissolved in a solvent with iron will work. Think of ammonium sulfate in water. Sodium Hyroxide in water. Carbonic acid. Oxygen gas. A higher temperature also increases the reaction rate.