Playscii - Full-featured ASCII art and graphic editor and game creation tool
Monodraw - Monodraw allows you to easily create text-based art (like diagrams, layouts, flow charts) and...
Charaster - Open-source ASCII art editor for browser-based, raster-style editing
JavE - JavE (Java Ascii Versatile Editor) is a free Ascii Editor.
REXPaint - REXPaint is a powerful and user-friendly ASCII art editor.
PabloDraw - PabloDraw is an Ansi/Ascii text and RIPscrip vector graphic art editor/viewer with multi-user capabilities.