Cabbage

Coleslaw is the world’s most popular salad based on cabbage.

An excerpt from the article 19 facts about cabbage

The current name of the salad originated in the 18th century and is the English version of the Danish name (in Danish koolsla means cabbage salad). It can be prepared in many ways, the ingredients can change at the cook’s discretion (carrots, cheese, pineapple, or apple) but cabbage is always its core ingredient. The most popular dressing used in salad is vinaigrette or mayonnaise (the former is much longer lasting).