What's out there, anyhow? [#DH]

From deep within a Twitter convo that started I don't know where:

pictures show what they show. The question we're posing is, what other literary phenomena not shown there might we investigate?

— Ted Underwood (@Ted_Underwood) August 11, 2017

More generally, what KINDS of things are there out there? That's one of the most important questions facing computational criticism.