Hi
Apple Watch Series 3 models are supplied with a Magnetic Charging Cable, a USB Power Adapter and an included band.
Apple Watch Hermès models also include a sport band in addition to the leather band. Apple Watch Edition models also include an Magnetic Charging Dock and a Lightning to USB Cable.
For more information about what is included with any model of Apple Watch, visit the product page on the Apple Online Store and see under the heading "What's in the Box". For example:
Apple Watch - Space Gray Aluminum Case with Gray Sport Band - Apple
Technical specifications for Series 3 models are detailed here: