Yes, there are definitely Medium publications.

As you read the work of your favorite Medium writers, check to see if a post has been published in a publication; this information will appear beneath the writer's name at the top of the post.

For instance? In my post, you'll see "Published in Ask an Editor" beneath my byline. You can explore that publication by clicking on "Ask an Editor."

Here is a list of Medium publications that can boost a writer's work:

https://help.medium.com/hc/en-us/articles/23964242497559-Browse-100-publications-in-the-Boost-Nomination-Pilot