You'll be hard pressed to find an actual direct Thunderbolt 2 to Ethernet adapter though. Those don't really exist.
You should be able to find a USB-A to Ethernet Adapter more easily.
For an example click here ➜ Ugreen USB-A to Ethernet Adapter - Amazon.com
If you don't want to use the USB ports on your Mac, and really want to use the Thunderbolt port then you'll need a more expensive dock. Converting from Thunderbolt to ethernet takes a lot processing of the Thunderbolt signal to turn it into a usb and ethernet. A simple adapter is never going to work.
click here ➜ OWC MacSales.com Thunderbolt 2 Dock - Amazon.com