A few things.

My favourite is a flow to pull HTML-formatted newsletters out of my email and push them to Wallabag. I then use Wallabag's RSS feature with Calibre to turn them into an ebook I can read on my Kindle.

My other major use case is centralized notifications. For a lot of things (e.g. backups), I have a webhooks in Huginn that then push out a notification via Gotify to my phone.

I've also used Huginn to scrub/clean up RSS feeds, since it can pull the feed, apply transforms to it, and then republish it.