The following radios and radio boards are compatible with OpenTX.

Tray version of Taranis Plus with:
Color OLED top mounted display for basic telemetry data
Quality 4 bearing gimbals
Bluetooth support
2 additional sliders
Safe start and safe shutdown power switch
Haptic vibration
Improved audio circuits

New version of Taranis with:
Haptic vibration
Multi colored LCD background light
Improved LCD display
Improved audio circuits

ARM Cortex M3 32-bit 120MHz
212x64 LCD with gray scales
60 models + infinite on SD
9 flight modes
Telemetry
Advanced audio functions (voice files from SD, vario, ...)
SD data logger

ARM Cortex M3 32-bit 36MHz
60 models + infinite on SD
9 flight modes
Telemetry Interface through Futaba trainer jack
Advanced audio functions (voice files from SD, vario, ...)
SD data logger

Arduino (or clone) MEGA2560 16MHz
30 models + infinite on SD
6 flight modes
2 rotary encoders (one can be used for navigation)
Telemetry
SD data logger

ATmega128 8-bit 16MHz
30 models
5 flight modes

ATmega64 8-bit 16MHz
16 models
5 flight modes
A lot of mods supported (audio, voice, telemetry, rotary encoder navigation, ...)

ARM Cortex M3 32-bit 36MHz
60 models + infinite on SD
9 flight modes
Rotary encoder navigation
Telemetry
Advanced audio functions (voice files from SD, vario, ...)
SD data logger

ATmega2560 8-bit 16MHz
30 models + infinite on SD
6 flight modes
2 rotary encoders (one can be used for navigation)
Telemetry
SD data logger