Some groups of vegetables considered “compatible” and safe to be rotated together include:

Alliums - onions, leeks, shallots; Crucifers - such as radishes, turnips, broccoli, cauliflower; Brassicas - brussel sprouts, mustards, cabbages, kale; Legumes - peas and beans; Cucurbits - cucumbers, squashes, melons, etcetera; Solanaceae - peppers, eggplants, tomatoes; and Mescluns - arugula, endive, radiccio, etcetera.