Mostly used Notepad++ or SciTE ( https://www.scintilla.org/ ) over the years, as the number of languages/platforms I traverse made it a consistent option for dealing with various document encodings etc.

I thought mc and mcedit was cool, but needed something small and portable within a fairly locked-down environment ( "No [root] for you!" as the admin would say.) =3

Many years ago, I used UltraEdit. It was fast, light weight(ish) and supported huge files.