In drupal 7 we had some contrib modules using a tag to make subtitles in our menu. In drupal 8 I try to avoid contrib modules on my menu items. Here's a hint on how to get it to work.
For a few months I'm working in my spare time on a module that can import instagram feeds and turn it into nodes. And on top of that, a nice javascript extension to make it look beautiful out-of-the box.
A thing developers can forget while testing, is to make sure all functionality of your module is stable when used in the context of ajax. Some plugins might stop working after an ajax call on the page. This is how to prevent such thing.
It is a bit strange that the name field (which functions like the node's title field) can be only 50 characters long. The snippet I'd like to share with you, makes it 255 long.