I have some ideas for item I just felt like throwing out there. I personally don't use advanced editor very often, but I could try it.
1. Stackable items
I think that there should be some way to stack items together, just so that if there were a way to make a farm, you could just stack the items you earn and not have to deal with the long list that you might get.
2. Randomized items
If you, say, killed a monster in the story, you would need a randomizer for the items. Because if you got the items guaranteed, that would be boring. And I don't think anyone wants to have to create entirely new page and randomize the chance for you to get it just to get a "random" amount of items.
3. Rogue items
If this is already a thing. I'd look pretty stupid. If you use an item, there should be a chance that it'll work or not work, or that it'll do something you don't want it to do. That would be useful.
4. Locked Items
If there was a consequence f you picking up a certain item, or not being able to pick one up, then that would be a little more interesting.
That's all I could think of. Please tell me if any of these already are possible, thank you.