I made an add-on that exposes a list of user defined home assistant sensor states in a simple HTML table for Poly (Polycom) VVX phones to display using their microbrowser.
I made this for my Polycom VVX 500.
Some more details in this post Home Assistant Dashboard on Polycom VVX - wtip.net with links to the repository.
Makes you remember when everything on the www was simple html.