[Quoth]

Nano: Quick configuration edits. It's on most embedded stuff too.
vi: For people that have frenimies that are emacs users. vim is more common now.
KATE: Multiple tabs per text file and persistent sessions for groups of text. Notepad++ is similar for Windows. May need Oxygen icons and some libraries etc for all of the GUI to work.
And for Novels and any other large projects, not pure text, LibreOffice Writer. Styles are your friend. Edit in odt format but SaveAs to export .doc, .docx, RTF, XML etc. Also not bad PDF and HTML export. Use Calibre (.docx to epub, then epub to others) for ebooks rather than the Writer 5.x plugin or 6.x built in epub export. Or if you are an emacs addict, then use Sigil to make epubs.

I use KATE and LO Writer in side by side windows. KATE has all the notes & resources in tabs, a session per book series/project. Four years ago I was doing that with Notepad++ and MSWord 2002. I've not used the serious UNIX text editors since the late 1980s, instead I've used Nano for last 12+ years at least on Linux.
I used Star Office, Open Office etc on Windows and Linux till it became LibreOffice, at the same time as MS Word. Completely abandoned Windows a couple of months after win7 sales ended for main laptop, though I'd been using Linux on servers since 1999, and dual boot since 2004 on laptops. Started with MS Xenix and Cromemco Cromix in mid 1980s in parallel with DOS. Used ordinary Windows from 1991 and NT from 1994.

Oh and I use Regex in KATE and LO Writer. An optional feature of Find & Replace.