Much like the Fire TV Stick 2 before it, the new Fire TV 3 supports external peripherals through a USB OTG cable. This means that, despite not having any external ports, you can still connect things like USB drives, keyboards, mice, game controllers, ethernet adapters, and more.
LAN Ethernet Adapter with 3 USB Port Hub with Micro USB Power for
OTG Cable for Fire TV Stick 4K Lite Max Cube, USB
UGREEN USB 3.0 Hub Gigabit Ethernet Adapter, 3-Port USB Hub
Everything you can do with the Fire TV Cube's Micro USB
Fire TV 3 supports USB Peripherals via OTG Cable
Oassuose 3 Pack OTG Cable Adapter for Fire TV Stick
HOXIBSL OTG Cable Adapter for fire Stick 4K Max,Added
USB OTG Cable Ethernet Adapter for Fire Stick 4K TV
AuviPal 3-Port LAN Ethernet Adapter USB Hub for Streaming TV Stick
4 in 1 Ethernet Adapter and 3 Ports USB OTG Hub for
Flirc Fire TV Edition - Flirc
Ethernet Adapter for fire Stick TV Cube, Google
HOXIBSL OTG Cable Adapter for fire Stick 4K Max,Added
Flirc Fire TV Edition - Flirc