Below are links to 3 of the most popular ansi screen creators/editors..
Pablodraw – is an Ansi/Ascii text and RIPscrip vector graphic art editor/viewer with multi-user capabilities.
Thedraw – This was a mainstay of the BBS scene
Moebius – Moebius is a new ANSI and ASCII Editor for MacOS, Windows, and Linux. The major feature that differentiates it from PabloDraw is the ‘half-block’ brush.