The best way to go is to buy 16" wheels with your desired bolt pattern and back spacing. Adding a wheel addapter can be safe, but it adds one more (possibly weak) link in the system.
You need to decide what size wheel you need, then find what wheels are available in that specific size. What back spacing are you looking for? What width? Will the desired tire be compatable?
If you want OEM wheels, look for factory Rubicon Moab wheels or knock offs.
Mamba Offroad Alloys R16865S13 - Mamba Offroad Type MR-1 Silver Wheel for Jeep® Vehicles with 5x4.5 Bolt Pattern - Quadratec