Four shadow families are confirmed
Skeletons, Zombies, Guards and boss units are the families named by the official Roblox description. Approved screenshots also show mixed armies made from skeletal, green undead and armored figures. That supports a family reference, but it does not prove that every visual variant is a separately named unit or that one family has a fixed combat role.
Use this page to check what each family is known for at the source level. For a decision about what to keep or build around, open the army comparison and team checklist. It deliberately avoids exact power tiers until comparable stats exist.