Some of the newer cards have often brought this to my mind: "I wish there be more ways to discard my own allies or attachments." There are quite a few ways to discard cards from hand, such as Erestor or Protector of Lórien. But recently there's a good need to discard cards in play, just to play them again and get the benefit of it: Lord of Morthond + Men of the West combo comes to mind, especially if the discarding also comes with a bonus (not only for the likes of Imrahil, Valiant Sacrifice, Horn of Gondor) but even more directly, just like Ride to Ruin works. I did like that card a lot when exploring locations was much more needed (or possible, as the locations were not only more numerous but also hardly ever immune).
Then there are attachments like Steward of Gondor that often provides too many resources that are hard to share (more easily though with the newer cards like Errand-rider). Still, it would be nice to be able to, well return it to hand or directly switch target would be even more useful but probably too easy. Discarding it feels just about right, so that you can play the other unique copy on someone else. And there are of course many, many candidates. Spare Hood and Cloak, for instance, has beautiful mechanic that can be used repeatedly, but sometimes it would really help to get rid of, only to bring it back (via Will of the West, Erebor Hammersmith, etc.), only to use it again from the scratch (using the obvious targets, such as Tactics Boromir).
This is just another aspect of the game that allows for interesting combos I always like to find. The hidden combo may not always be super effective but the joy of finding it is certainly deserving, and worth the struggle for it.