The save manager supports any type that is serializable by Unity by default. This means your common types like bool, string, int etc. as well as Array & Lists. You can read more on the serialization here: https://docs.unity3d.com/Manual/script-Serialization.html
The only addition in this asset is the support to save a dictionary using a custom SerializableDictionary class. The class just stores a list of a custom key pair class that is serializable. The asset uses this for its lookups and you can use it in your code should you wish.