Sweet fruit: One of the fruits is often sweet: grapes are best! Lychees are amazing! Rambutan is like lychees. Both lychees and rambutan are found in Asian grocery stores. Pluots, nectarines and peaches are also great. Mango also works well. Out of all these fruits, I love grapes, lychees and mangoes the most!

Sweet n sour fruit: The second fruit is often sweet n sour, for example, orange. Pineapple and plum should also work well.

Fresh berries: I throw in some combination of blueberries, barberries and strawberries, whenever I have these at home.

Berry powder: Sumac is a spice. It is basically dried sumac berries, crushed into a powder; popular in Mediterranean cuisine; tart flavor. Maybe we can add ⅛ tsp amla powder (gooseberry powder); I've never tried that.

Dried berries: We can also rehydrate frozen berries like dried mulberries, dried goji berries, dried sweet cherries, dried unsweetened cranberries, dried jujubes, dried golden berries. These berries are amazingly flavorful and enhance the taste of any salad.