David Aylward
Typescapes, 1967.
RTTY babez dating back to the 1960s. RTTY art was around before ASCII was even defined. It uses special keyboards and typewriters to send text messages using radio waves. It was probably used for text graphics already in the 1920s.
Instead of ASCII, it (usually) used the Baudot code, which is almost 100 years older than ASCII. All images here taken from the Roy/SAC collection, where you can get both the original data, and a lot of the original photos.
Density by K.O Götz, 1962. Although technically more similar to pixel graphics, this computer animation looks rather textmode to all the whales in the house. Also available on archive.org.
From Playboy, October 1967.
2024-update: not sure if we got this from here, but this exact page was featured in a custom-made Playboy issue for Forrest Gump in 1994. It was dated to July 1966.
Autopoem Nr. 1 by Gerhard Stickel, 1965. Generated with an IBM 7090.
Répartition aléatoire de 40 000 carrés, 50 % noir, 50 % blanc, a painting by François Morellet, 1961.
More Morellet
Walk-Through-Raster serie 2.1 by Frieder Nake, 1966. Programmed in ALGOL 60, plotted with a ZUSE-Graphomat Z64. More info here and here.
Density 10:3:2:1 (1961) and Statistisch-metrischer Versuch 4:2:2:1 (1959) by Karl Otto Götz, who still made art when he was 100+ years old.