Loot Filter is nice when you want to keep everything but a certain type of item. I'm currently using it and it's indeed very helpful. But I'd also like to see something a bit more specialized(?) than that.
For me, when I'm looting crates/sacks/barrels, I'm looking for a few select ingredients. Everything else just takes up space. The simplest thing would be to turn off auto-loot, sure, but I also harvest a lot of ore and plants, which can become tedious without auto-loot imo. So right now I leave auto-loot on and just have to delete the stuff I don't want/need when my bag fills up.
I'd like to see an addon where I can be general (all ore/plants) and specific (only these items from crates/etc) at the same time. Of course I've no idea if that's possible or reasonable, but just wanted to throw it out there.