A block which can simply display any web URL. This block would allow Airtable to be a more complete dashboard.
For product-focused teams working on prototypes, device frames could be a nice touch (e.g. show your web app on an iPhone, like pasteapp.com).
In addition, if that URL could be constructed from data, e.g. where selected table values can be appended to the URL as querystring, that would open up a world of possibilities to craft very simple bespoke web pages / product prototypes which react in real time to data changes.