Sago with coconut milk works as a fantastic base to many other flavors. My recipe calls for fresh, sweet mango. But make it your own and change it up with seasonal fruit.
Other suggestions:
Strawberries
Blueberries
Passionfruit
Pomelo
Fruit puree (mango puree, strawberry puree, passionfruit puree)
Taro
Sweetened Condensed Milk (a drizzle is very good!)