Speaking about shows with no gore scenes "Happy Sugar Life" anime deserves guro title most of all.
It includes almost all kinds of insanities and perversions almost nobody is sane there.
this anime can be educational psychiatric material. I would recommend it for exactly that reason to get a better understanding of human psychology.
Also, it could be a perfect illustration of the meaning of "hell"

At least for me, there are no characters to whom I could relate myself, this why it makes it more enjoyable. No need to worry if someone dies they all deserve that LOL


Another western guro show is Superjail!
Which is almost non stop gore and guts flying all around if only all those ugly guys were drawn as cute girls:)


and finally, one very unexpected show is "Futurama" which is actually that perfect word of guro utopia.