BBEdit★★★★★Text editor for macOS that’s powerful enough to handle multi-megabyte files and still light enough to jot down notes.
FeatherPad★★★★☆A lightweight, fast, stable, and capable text editor for Linux.
Notepad++★★★★★A perfect balance of powerful and lightweight, Notepad++ is far more capable than Notepad, but doesn’t complicate things like a full IDE.
QuickEdit★★★★★Full-featured text editor for Android. Good in a pinch on a phone, better on a tablet.