From myself malice
Hive webtoon
Omoide emanon (I think you read this already?)
Rock n Roll Rikitaro
Daihakken
Momonchi
Again!!
Lookism
My Brother the Shut-in
Shino-chan can't say her own name (don't think Oshimi is obscure around here though)
51 Ways to Save Her (didn't love this, but it is decent and it's a unique story. Jakjak found/liked this one)
Not sure what counts as obscure. I'm too far down the rabbit hole. Just named some that don't have an anime, although some might have live action dramas or movies. Looking through my list reminded me of how many manga built up over the last 9+ years I should probably try to get through before finding any more series.
I'm sure Kenshi and Kyouks (peas in a pod) will come in with some super weird, bottom-of-the-iceberg obscure stuff.