Here are some you that might be up your alley:
Kasane - Ugly and disfigured theater girl gains the ability to steal peoples' faces, leaves a chaos of revenge and drama in her wake.
Bokurano - Used to be more well-known a decade ago, but I see much fewer people ever bring the manga up nowadays. Utterly miserable, yet enjoyable.
Fujimi Lovers - Guy is chasing after girl and her various incarnations, but every time he confesses to her she is erased from the universe.
Rojica to Rakkasei - Short storybook-like stories, each with a not-always obvious dark implication. Linked together by an overarching plot and the peaceful father-daughter duo of Rojica and Rakkasei.
Freesia - Dystopic wartime government introduces a ritualised, state-backed revenge system. Story follows a schizophrenic vet joining one of these revenge companies and its targets.
Uratarou - Odd little series that starts off as an average shonen battle manga, but quickly goes off the rails after the series receives an axe announcement and is given enough time to wrap things up.
Misu Misou - Middle school bullying by the largest collection of little shits reaches its breaking point, erupts in violence.
Mouryou no Yurikago - An earlier zombie story by Sanbe Kei before he fully became "the thriller guy". Featuring all the usual octopus lips, brown girls and attachment to secondary characters.
