If you're experimenting with more advanced prompts, using {red|green} in a prompt introduces the first bit of randomness. Soon you'll be looking at text processing nodes. But the basic set seems very limited, and custom nodes are inconvenient.
The attached blueprint is very simple. You feed it an input text like red;blue;green and it will pick one at random as output. (You can also put every entry on its own line, i.e. separate them by \n).
There's a lot you can do with this, but one of the easiest things is to wire it to a ReplaceText node. Replace "{color}" with the randomly chosen output of the blueprint, and you get almost the basic functionality of the standard prompt - but with a twist: you can use {color} twice in the input, and the ReplaceText node will consistently use the same color. This makes it a lot easier to get color-coordinated items in your output. For instance, the red and green letters in my cover image.
(You can use {color1} and {color2} to get two independent choices, but you of course will need to wire up two instances.
