Considering Isekai is basically just fantasy with extra steps, take a look at Frieren if you haven't already. It's fantasy without the Isekai gimmick, following the story of an elf that outlives all her travelling companions, and retraces the steps of her journey with them to remember them. Very wholesome, slow paced and melancholic - even sad at times.

Ascendance of a Bookworm is another, following a library mega-nerd that isekais into a little sickly girl, and follows her story as she works towards creating the entire goddamn book industry all the way from creating paper from scratch.

Dr. Stone is potentially another example, not strictly iseka with the whole reincarnated gimmick, but "petrified for a few thousand years" and waking to a post post post apocalyptic stone age setting is basically the same anyway. Follows a science mega-nerd that starts recreating modern science from scratch.