Kore is an excellent Android remote control for Kodi (running on any platform). It has all the controls you need in one place - even an onscreen keyboard for any text input and pause/start, fast forward & fast rewind to control audio and video. Details:
Amazon Fire TV Remote App for Android. Easier to use than the remote control that comes with the Amazon Fire TV - mainly for the onscreen keyboard for text input.
Wukong TV Remote Control for Android. This app is impressive, it has 4 modes of using it as a remote, these are: Classic Fire TV, Gestures, Mouse & Keyboard. For some sideloaded apps, Drop Box, ES File Explorer, Chrome Browser, Firefox Browser, Popcorn Time & others, the 'Mouse' mode is essential. The biggest drawback of this app is the Keyboard mode - it only has numbers. I've not tested/used Gestures. The thing that gives this app the edge over others is its 'Quick Launch' - launch any of your Fire TV apps, including sideloaded ones, from your phone/tablet. It also has an 'App Manager' section which I have not tried yet. If it had a full keyboard I would not need anything else.
Kassi - Kodi/XBMC Remote Control for Google Chrome & Firefox click the installed button and you have a fully featured Kodi remote - including text input.
Kodi (on Amazon Fire TV) Web Interface Remote Control Open Windows Explorer (not Internet Explorer) in Windows 7, go to 'Network' and you should see an entry for Kodi (localhost) in the 'Media Devices' category. Right click on it and select 'view device webpage'. The Kodi webpage will then open in your default web browser. Select the 'Remote' tab for a functional remote control for Kodi.
Amazon Fire TV Remote Stops Working
If your Amazon Fire TV Remote stops working, as it did for me today, firstly, using one of the apps above, go to the Amazon Fire TV Home > Settings > Controllers and Bluetooth Devices > Amazon Fire TV Remotes > Amazon Fire TV Remote - If it says anything other than 'OK' against battery then follow the instructions to unpair, then select 'Add New Remote' to (re)pair. Of course there may be other reasons its not working - dead batteries or broken remote, following this guide will help you determine the problem.