Pablodraw (based on Mono) is working but no longer fully maintained, it has been the de facto standard editor for over a decade.
Moebius (based on Electron) is a newer editor with unseen features like halfblock brushes
- Sixteen Colors draw: http://sixteencolors.github.io/js-textmode-editor/
- ANSI edit: http://andyherbert.github.io/ansiedit/public/index.html
- TheDraw: The godfather of ANSI editors and still the best for ansimation: http://www.syaross.org/thedraw/
- ACiDdraw: http://www.acid.org/apps/apps.html
- Empathy: ANSI editor with custom font feature to create XBIN’s https://files.scene.org/view/graphics/groups/acid/empd-100.zip