Substack’s “Discover” page can be reached in one of two ways: either straight from the home page or from the Reader at https://reader.substack.com/discover. In either case, you’ll find a set of tags or topics that look like this:
“Literature” is one of the listed topics but it’s hidden by default: you have to click the plus sign to get to it. I wondered if there might be an address or URL that would take me straight to the Literature page but I haven’t been able to find it.
So, for now, if you want to look for Substack newsletters on the topic of Literature, you’ll have to go to the Discover page and click the ➕ first. Unless anybody knows different.