https://github.com/rougier/nano-emacs (haven't tried, but clean look and defaults)
https://github.com/rnkn/olivetti (writing environment)
https://github.com/rnkn/fountain-mode (screenplay writing)
https://github.com/alphapapa/org-sidebar (sidebar)
https://github.com/jrblevin/markdown-mode (markdown, with preview too)
https://orgmode.org/ (of course, org-mode for everything)