It took me a moment to figure out that “rover” was the tenth category, but {-moH} isn’t the only singleton; there’s {-neS} as well.
I've seen (and heard) another Type 8 suffix used on a few occasions. It's not in any dictionaries, and it's possible that I'm the only one who noticed it. Its context has been similar to the use of a {bang pong}, and I will respect its users' privacy.
-- ghunchu'wI'