A pleasant byproduct of the growth in digital signage is the lowering cost and wider availability of LED matrix displays suitable for use in Arduino and Raspberry Pi projects like this one from Adafruit. Many of these displays conform to a connection standard called "HUB75" and so can be controlled by self-contained programmable interface boards or adapted for use with separate microcontrollers.
Adafruit has developed their own "Protomatter" software interface library that makes it easy to animate HUB75-compatible displays using Circuit Python or Arduino. I'm enjoying experimenting with a 32x64 LED matrix panel and have collected various sketches here.