Moshling Sets are groups of 4 moshlings. There are different Moshling Sets to collect like Dinos, Ninjas and Kitties. Moshling Sets can be found in Moshi Member's Moshling Zoos with different names to do with the Moshlings in that set. Each Moshling Set have 1, 2, 3 or 4 Moshlings in each of their categories.
Each time you complete a set, a pattern can be seen behind the 4 moshlings. Some sets can only be completed if you are a Moshi Member because they require Super Seeds which can only be found at The Port.