I’ve tested the wildcard extensively in Anima. As only Danbooru tags were used, the wildcard will also work for Illustrious and all other Danbooru-tag-based models.

The wildcard can be easily extended; furthermore, the weighting can also be adjusted if a specific style is required.

The higher the number, the greater the probability

I would simply recommend the

__simple_underwear/random__

to use because it contains all the expressions