Google Assistant - Get things done with Google Assistant
Mycroft.AI - Mycroft is the world’s first open source assistant.
Cortana - Cortana is your personal assistant.
Rhasspy - Rhasspy transforms voice commands into JSON events that can trigger actions in home automation software.
Amazon Alexa - Virtual assistant developed by Amazon
Braina - Braina (Brain Artificial) is an intelligent personal assistant software for Windows OS that allows you to interact with your computer using voice commands.