I have a question, How do you tell what the specific theme of a particular Booru is? I mean some are obvious by the name; "size booru", "furry booru" and so on. But not all are named so plainly, and I can find no pages that spell out what each booru is about, let alone what type of images should or should not be posted there (aside from the unilateral "no loli/shota"). For example, what kind of images would I find or should I submit to the board "clop"?

Shouldn't there be something somewhere that delineates what a particular board is about?

Yeah the owner can customize their booru to a certain style, but not all choose to do so and there is no requirement to do so.