Astra by Cesbo - Talk to Alexa anywhere, from your iPhone
Google Home - Set up, manage, and control your Chromecast, Chromecast Audio and Google Home devices.
Reverb - Use Alexa on your Mac, iPhone and Android
Facebook Portal - Smart, hands-free calling, with Alexa built in
API to bot - Convert your API to Alexa skill or Google Home app in 5 mins
Calaos - Open source home automation