I did a lot of fic based off their prompts a couple years ago, and still keep track of their posting just in case I get in the ficcing spirit again. Anyway, they've made some changes recently, including creating AO3 collections for their fics!
I spent an hour or so yesterday adding all of my comment fics already on AO3 to the relevant collections - the collections go by year, and you add your fic to the collection for the year you wrote it, plus the year the prompt was made if it was an older prompt. Volunteers are going through old posts and using the outside bookmarking function to link to comment fics not on AO3, as a prompt fill search function for the comm. If you've got some time, or comment fics already crossposted, why not add yours to the collections?