A trope was used, but then is stops being used.
Like it's said, Tropes Are Tools and you need to use some of them to make a story, and some tropes are used all the time in the same work. But as time goes by, some tropes are removed from works that used them in the past, this is the Discarded Trope, when a work used a trope, most of the times in the straight form, but them they completely remove it, it's just like an aversion, but the difference is that the trope was there before. There are many reasons why that happens, the best example is when a trope is discredited, it was ok to use that trope in that time, but time went by and it's a better idea to stop using it, another reason is a change in the work like a Genre Shift or Tone Shift, regardless if it's for the best or for the worse, to make the work different, some tropes will have to be discarded, there's also when the trope becomes unnecessary, is not going to be missed and then it's better to just remove it, and sometimes it just goes away with no clear reason. Contrast Grandfather Clause, when a trope is discredited, but they have to keep using since it's a tradition. Tropes that are often discarded in recent works: