Isekai / Reincarnated TRASH [DO NOT READ!!]

Trash story
https://www.novelupdates.com/series/reincarnated-as-the-son-of-a-vicious-lord-when-i-was-having-fun-learning-magic-i-had-to-get-rid-of-my-stigma/

Harem
https://www.mangaupdates.com/series/l510r5z/akutoku-ryoushu-no-musuko-ni-tensei-tanoshiku-mahou-wo-manandeitara-omei-wo-henjou-shitemashita

Plot holes + other Red Flags Harem, Polygamy
https://www.novelupdates.com/series/arafoo-kenja-no-isekai-seikatsu-nikki/

https://www.mangaupdates.com/series/icx5fgc/arafo-kenja-no-isekai-seikatsu-nikki

Yuri
reverse isekai
https://www.mangaupdates.com/series/z41zgbd/houkago-saitensei

https://mangadex.org/title/41d92f65-9277-4ce2-9ccd-cc2edb965f6d/houkago-saitensei

Polygamy & all red flag tags

source:
https://www.novelupdates.com/series/garbage-brave-isekai-ni-shoukan-sare-suterareta-yuusha-no-fukushuu-monogatari-ln/

Harem, Polygamy & Shoujo-ai

source:
https://www.novelupdates.com/series/a-sword-master-childhood-friend-power-harassed-me-harshly-so-i-broke-off-our-relationship-and-make-a-fresh-start-at-the-frontier-as-a-magic-swordsman/

Harem, Polygamy
https://www.novelupdates.com/series/otherworld-nation-founding-chronicles/

Red flag tags
https://www.mangaupdates.com/series/jpuaa4f/isekai-kenkokuki

Harem, Polygamy
https://www.novelupdates.com/series/legend/

Red Flag tags
https://www.mangaupdates.com/series/2tq1u8x/legend-takano-masaharu

Harem
https://www.novelupdates.com/series/murabito-desu-ga-nani-ka/

Red Flag tags
https://www.mangaupdates.com/series/9v9g4hv/murabito-desu-ga-nani-ka

https://comic-walker.com/contents/detail/KDCW_FS01000040010000_68/

Harem, Polygamy, shoujo-ai subplot

https://www.novelupdates.com/series/the-world-of-otome-games-is-tough-for-mobs/

Ecchi, Harem
Trash plot.
https://www.novelupdates.com/series/walking-in-another-world/