Neovim is a free, cross-platform text editor based on Vim, and is arguably the best editor currently in existence. Although Neovim is admittedly better suited for writing code than prose (largely because of its awkward handling of soft-wrapped lines), I use it for pretty much everything. Emacs is a free, cross-platform text editor, mail client, news reader, organizer, and more. It is the second-best text editor currently in existence. It does not take the streamlined, minimalistic approach that (Neo)Vim does, but it can be made to emulate Vim. I use Emacs for the excellent Org mode. See my emacs.org file for more.