Juicy tomatoes, crisp cucumber, tangy red onion, and fresh herbs like basil and parsley pair perfectly well with avocado. According to the vegetarian flavor bible from Karen Page, other ingredients that pair well with avocado are asparagus, black beans, corn, fennel, garlic, grapefruit, greens, lemon, lime, lettuce, mango, orange, quinoa, scallions, spinach, and yogurt.