REXPaint

REXPaint is a free, user-friendly ASCII art editor that allows users to create ANSI block/line art, roguelike mockups, UI layouts, and more. It offers various tools for editing characters, colors, shapes, and text, as well as features like copy/cut/paste, undo/redo, zooming, custom fonts, and true-color RGB/HSV/hex color picker. With its image-wide color tweaking, palette swaps, and support for extended characters and tilesets, REXPaint is a powerful tool for game developers and artists.