When I used to teach community college classes, one thing I was loathe to do was provide the definitive list of indicators associated with each cryptic device. You know, a lesson on anagrams is ended with a couple of pages of anagram indicators, and a lesson on hiddens isn’t complete with words to look for that may signify concealed text. But although people love lists of this kind, it’s dangerous to rely on them as there’s no way to create a list that will capture every indicator that will ever be used for a particular device. And you wouldn’t want to, as this would limit the creativity of the setter AND stop the solver from exploring the depths of clues.
Some people have attempted to create the best lists by reverse engineering, that is, poring over clues and extracting the indicators used, believing that if an indicator is published in a newspaper, it must be acceptable – this of course is nonsense and can lead to proliferation of unacceptable device indicators.
The lists I created for my community college lessons would have just the indicators that I considered represent what the indicators are supposed to be doing. That is, not comprehensive at all, more just capturing the different types of indicators that a device might use. Lists often contain the base words only, which in itself is dangerous as only when an indicator is used properly (right tense, right grammar, right location) is it really doing its job. I used to say that my list points them in the right direction – what they are looking for in an anagram, for example, is ANY word that suggests change or a mixture, which is fairly broad, but not limiting, which is what a list can tend to do.
Homework each week consisted of going through a local crossword highlighting any word the students thought could be an indicator of sorts. I didn’t care if it was or wasn’t, I wanted them to consider all the possbilities that a word or phrase had to offer, so as not to restrict them in their thinking.