Something that greatly differentiates the Fire TV Cube from the Fire TV 3 is the Cube's Micro USB port and the official support for expandability that comes with it.
DSYJ Micro USB Host OTG Cable with Micro USB Power for Samsung S7 Edge, S6 Edge, S5, S4 & Nexus 10 9 7 4 Player + All Others 2 Pack : Cell Phones & Accessories
Control your Fire TV with almost any remote. Compatible with Harmony Flirc’s easy-to-use software walks you through the entire pairing process and works on Windows, OSX and Linux Simple connection. Plug directly between your Fire TV and the USB power cord As fully featured as the original Flirc USB in an all new body Flirc Fire TV Edition is a universal remote control receiver. It allows you to pair any remote control with your computer or media center.
Flirc USB Fire TV Edition
FLIRC USB Universal Remote Control Receiver : Electronics
Oassuose 3 Pack OTG Cable Adapter for Fire TV Stick 4K Max/Cube/Lite,Powered Micro USB to USB OTG Adapter Compatible Android Smartphones,Tablets,Host Devices etc : Cell Phones & Accessories
DSYJ OTG USB Cable Plug and play: Simply connect the micro USB male port to your host devices and the micro USB female port to your usb power cable,
Micro USB Host OTG Cable with Micro USB Power for Samsung S7 Edge, S6 Edge, S5, S4 & Nexus 10 9 7 4 Player + All Others 2 Pack
External Storage Support Explained Across All Fire TV Models — Fire TV Stick 4K vs 4K Max differences and more
Flirc Fire TV Edition - Flirc
Everything You Can Do With The Fire TV Cube's Micro, 55% OFF
Yonisun Micro USB Host OTG Cable with USB Power for Samsung/HTC/Nexus/Lg Phones and Tablets : Electronics
Flirc Fire TV Edition - Flirc
Everything you can do with the Fire TV Cube's Micro USB port — Ethernet, App Storage, External Drives, Peripherals, FLIRC, OTG, and more
Add extra wired Ethernet & USB 3 ports extra storage to your streaming device for connecting wired network,flash drive,wireless keyboard or whatever
4 in 1 Ethernet Adapter and 3 Ports USB OTG Hub for Fire TV Stick 4K/Chromecast/Google Home Mini/Raspberry Pi Zero and Other Streaming TV Sticks,Micro