I need to be able to validate a fully qualified domain name (FQDN). This has a few differences in comparison to Joi.string().uri() and Joi.string().hostname(), such as it requires a valid TLD, doesn't have a schema, and can't include a path.

It doesn't necessarily have to check against a huge list of valid TLDs, but at least check for a TLD. You can see how they do it in this example from validator.js.

I'd be happy to submit a pull request for this, just lmk.