Hi Jamie, unfortunately Medium doesn't offer a list of all publications but they are working on proving one. I know... there are hundreds who aren't active anymore. The search is horrible so you'll find writing challenges from 2021 for instance.

Sometimes writers provide a list with pubs that are open for submission for 2023... I'd look for those types of stories. I'm also in the middle of creating a list for new writers. What niche are you looking for?