For me, 'That Time I Got Reincarnated as a Slime' stands out. The world-building and plot development are really engaging. Also, the characters have a lot of depth.
Well, it's a bit hard to pinpoint exactly which was the very first one. But some early examples could include 'El-Hazard: The Magnificent World', which had elements of the isekai genre.
Hentai manga isekai typically features outlandish settings and sexual content. The storylines can be quite unconventional and focus on fulfilling certain fantasies. However, it's important to note that such content may not be suitable for all audiences.
Isekai Quartet indeed has a manga. It offers a different perspective and sometimes delves deeper into the story compared to the anime. The manga can be a great companion to the animated version for fans wanting more of the Isekai Quartet world.
Isekai skeleton manga usually has unique worlds, powerful characters, and exciting adventures. The skeleton protagonist often has special abilities and has to face various challenges.
I'd recommend checking out online manga libraries such as Comixology or Crunchyroll Manga. They often have a good selection of isekai titles. Also, some local libraries might have physical or digital copies you can access.
It usually involves a complex relationship story where the characters face challenges and emotions related to not having children. The plot can be quite intense and emotional.
The 'A Foreign Affair' manga has been well-received. It offers a fresh perspective and has a good balance of drama and adventure. Though it may not be for everyone, it has a dedicated fan base.