
Saline solution is salt dissolved in water and dosed by the drop, a way of salting a drink without a rim or a crunch.
Salt is the ingredient; the form only decides whether you can dose it. A solution exists because grains dissolve unevenly in a cold drink and a few too many cannot be taken back. In a shaken drink that matters less, since the shaking does the dissolving.
Flaky or rimming salt
Dry, uneven and slow to dissolve, it seasons the lip of the glass instead of the liquid; that is a different effect altogether.
Celery salt and other seasoned salts
These carry flavor along with the salinity. Saline is meant to adjust a drink without announcing itself, and a seasoned salt announces itself.
Salt water does not spoil. Keep it capped so it does not concentrate by evaporation, which would quietly make every dose stronger than the last.

Cosmopolitan Cocktail (1934 recipe)
London dry gin

Italian Mezcal Margarita
Tequila reposado

Mango Vodka Sour
Mango vodka, Mango liqueur

Mojito (Cuban-style)
White rum

Rhubarb Gimlet
London dry gin

Spicy Tequila Espresso Martini
Tequila blanco

Strawberry Daiquiri
Light gold rum

Caramel Whiskey Sour
Bourbon

Negroni Flip
London dry gin, Red bitter, Carpano Antica Formula vermouth

Pomegranate Cosmopolitan
Vodka

Sake Negroni
Red bitter, Sake, Dry vermouth

Espresso Margarita
Tequila reposado

Raspberry Margarita
Tequila reposado

Amaretto Stone Sour
Amaretto liqueur

Gold Rush
Bourbon

Mock Margarita

Raspberry Martini
Vodka

Spiced Margarita
Tequila blanco

Watermelon Cosmo
Watermelon vodka

Blood Orange Daiquiri
White rum

Bourbon Smash
Bourbon

Cherry Margarita
Tequila reposado

Cucumber Rum Collins
White rum

Oriental Tartini
London dry gin