I recently came across the New York Time’s list of 401 prompts for argumentative writing. This would come in handy in many an EAP classroom, where opinion or argumentative essays in various forms are taught at most levels, really. The topics and questions are such that most of them could form the prompt for an essay being written purely from a student’s own background knowledge, experience and opinions, or for a research essay drawing on external sources of information.
There is also a list of prompts for personal or narrative writing, along with a lesson called “From ‘Lives’ to ‘Modern Love’, Writing Personal Essays with Help from the New York Times”. It’s true that those two particular sections/columns in the NYT are particularly interesting and engaging; not to mention that there’s an archive with thousands of relatively short, easy-to-engage-with texts that could be mined for any number of uses in a writing class.
Also fun to use would be the daily picture prompt. This could be especially flexible for use with lower levels, or as a prompt for genres other than the essay, such as creative writing.