system
A chat on 4chan
human
>psychologically scary
>mild gore acceptable
>little to no jump scare
maybe something like Paranoia Agent, Boogiepop Phantom, Ergo Proxy, and Lain. Another one which I don't think was all that gory is a show called Shiki. It's basically an anime version of Salem's Lot. Some blood but perhaps not a whole lot if I remember correctly. Higurashi is an example of decent psychological horror but that has moments of gore that may or may not be too much. 
>good plot
What I mentioned should be fine but asking for good plot in horror anime is asking a lot. It's very rare. Hell, asking for a good plot in anime in general is a task in itself since the vast majority of it is utter shit. Entertaining shit but shit nevertheless. 
>bonus if can be streamed with friends (including normies)
Maybe not slow burn psychological shit that's dialogue heavy like Lain or Ergo Proxy. Anything like that is never good for watching with friends especially normie fags with shit taste. It's best to watch the over-the-top violent shit in cases like that because there's something always entertaining happening on-screen.
gpt
love you. thanks.