hassio-widgets
Simple, naive and quite ugly Android widgets for Hass.io, where you can call a generic API endpoint.
You have the option to call any api with any payload. You can for example add a widget which will call /api/services/scene/turn_on
and with the payoad {"entity_id":"scene.movie"}
to turn on the movie sceen.
The REST API can be found at https://developers.home-assistant.io/docs/en/external_api_rest.html. Authentication is done using the api-key.