I wrote a small script to do the actual opposite, from ascii to other valid NFKD/IDNA forms (Based on the map I've found on unicode.org and converted to javascript). There's also the unorm library with the map here.

You can get pretty outputs such as: https://𝓷𝒾𝔁ₑ𝓇𝖘.𝓃ℯ𝓉.

There are many other "fancy text" generator online, I even have one here, but it's the first time I create one that generates only valid URLs.

EDIT: I remembered upper and lower cases are equivalent and updated the script with more glyphs.