BingingEnthusiast

https://www.mangago.zone/read-manga/zankoku_na_kami_ga_shihai_suru/

Have you heard of this majestic thing called Banana fish?
If you want a full ride of despair, start with California Monogatari, then Banana fish and it's extras(there are some that are not on here), from there Yasha, and to top it off Eve no Nemuri
I would say that especially Banana fish does a great job of portraying it's time period, writing complex characters, telling a story, and collecting all of the trigger warnings to ever exist. (If you have watched the anime, it might not go as hard, but it makes so much more sense than the anime and is an a lot more of an experience and a full story)(as a person who went in without a single warning (years ago) that thing crushed me)

I'll go contemplate on other things to recommend.
Some find Ten years I loved you the most sad, so maybe try it if you didn't yet

https://www.mangago.zone/read-manga/an_uncomfortable_truth/
this one was pretty messed up definitely lived up to its name

I’ve definitely seen banana fish before I still refuse to believe the ending is real, I’ll check out the other stuff!

I’ve read it already but maybe I should do it again

https://www.mangago.zone/read-manga/pumpkin_night/

https://www.mangago.zone/read-manga/feeding_lamb/

https://www.mangago.zone/read-manga/heartless/

https://www.mangago.zone/read-manga/the_rib_of_adam_jinmi/

All of harada's works

As a rather insensitive person, majority of these were ok or not that much, but some of them are good manga, gore, art style:
Shoujo Tsubaki and other words by the author
Rainbow: Nisha Rokubou no Shichinin
Devilman
Barefoot Gen
Works of Nishin Masumi that are not on this website
Pet shor of horrors
[SHIMESABA (Isaki)] Inu no Shitsuke (not on magago)
Human race for food ()
Jinmen
Working of TOMITA Douji (i really love them, wouldn't say that they're extreme tho)

(Also have a list of gore anime if you would like)

Maybe give a try to (less gore more common sadness):
Yunagi no Machi Sakura no Kuni
177013
Keimusho no Naka
Gunslinger Girl
Saikano
oyasumi punpun (popular and worth it)
Erased (was a very so-so thing for me, but I know people who couldn't handle it)
Jumyou wo Kaitotte Moratta. Ichinen ni Tsuki, Ichimanen de.
Black lagoon,( but it's not the manga itself, rather if you go digging about the actual history things are based on)

I would say that it's worth reading even if you watched the anime, because:
It's better, has a great art style (part 3rd volume, until then the author was figuring things out), has much more info about characters, even more messed up. And some of the extras won't make sense if you don't read it.
And just my favorite manga overall and I love suffering every time I think of it

Then I definitely have to read it again and everything else you’ve dropped here, thank you!

Read all of them except the last one (and of course, harada’s works are great reads as well, waiting for a new release fr)

Not tragedy but makes you cry like no tomorrow:
https://www.mangago.zone/read-manga/itou_san_kuraka_sui/
https://www.mangago.zone/read-manga/kami_no_fune_de_nemuru/
https://www.mangago.zone/read-manga/a_room_without_space_side_story_1/
https://www.mangago.zone/read-manga/500_nen_no_itonami/

Tragedy you won’t overcome:
https://www.mangago.zone/read-manga/haruka_tooki_ie/
https://www.mangago.zone/read-manga/perle/
https://www.mangago.zone/read-manga/lonely_to_organdy/

The anime is amazing but the manga is a whole other thing

You”re funny for recommending that last one because what the fuck did I just read

Then I looked at the comments and it said lowest rating they!d ever seen, the 4.7 is SENDING me

A list of gore anime would be great, I’m taking my time going through everything here but feel free to send more!

Only ones I haven’t read here are the last one in the first category and the first 2 in the second, definitely gonna read

You won’t regret it