I find it interesting that part of the reasoning for the <toast> is this:

"Many libraries in a variety of frameworks implement a version of toast (see research), but the web has no built-in API to address the use case." [1]

One thing I would love to see as a browser handled web standard is the cookie notice and gdpr opt-in for a given web page. Every European site has a requirement to include that if they use cookies or ask for personal data, but there is no method of making it a web experience across the web.

Unless I can do this of course:

  <toast>
    <button>Accept cookies</button>
  </toast>

[1] https://github.com/jackbsteinberg/std-toast