Facebook is an extremely useful tool for networking, promoting your name, building online credibility, and discovering potential publishers. The list below is of 6 Facebook groups focusing on submission calls. This list is for more than just poets, but all forms of writers of all genres.
#1 is the group I use the most, as it has a high focus on poetry markets, though there are many postings for creative essays and art submissions as well.
Hopefully this list finds you all well, and helps you discover your next publisher.