Lexi - Speak to Alexa through your iPhone
ifttt - IFTTT puts the internet to work for you. Create simple connections between the products you use every day.
Astra by Cesbo - Talk to Alexa anywhere, from your iPhone
Mycroft.AI - Mycroft is the world’s first open source assistant.
Ava - Making conversations accessible for the deaf
Google Assistant - Get things done with Google Assistant