Hi! Not sure if you're still updating this or answering, but I've come across something that I can't make sense of:

主コメ

Translations that I go to translate it as "main rice" which...doesn't make a lot of sense. So I assume it's some kind of slang?

Thanks for this list, by the way! I've only recently started watching a bunch of Nico Nico videos and this has been really helpful.