FiiNote - FiiNote is the most convenient note app for android.
Coastline - Simple minimalist text editor. Create, open, edit and save plain text files.
jEdit - jEdit is a mature programmer's text editor with a large collection of plugins
Nebulous Notes - Nebulous Notes is a powerful, yet simple, text editor for note-takers, writers, and coders.
Google Keep - Capture notes, share them with others, and access them from your computer, phone or tablet. Free with a Google account.
Jota Text Editor - Jota, pronouced as "i-o-ta", is a text editor designed for a long text file.