Not sure if it's been suggested before, but I didn't find anything.
How about a Potion of Luck, that increases your luck of finding items for a couple of minutes/turns? Maybe it just makes it more likely to find magical items, or, as I think, all items. It could be added to already added content as,
Any +1 or -1?
I came up with this idea when having bad luck for some runed scepters I wanted to have to gain some gold.
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EDIT:
Oet wrote:Just another idea I came up with while writing this, that would be cool, if someone agrees with me.
What if the Potion of Luck gives you a (let's say 10%) chance to get 2 items instead of one when it drops.
So, every item you loot while using this has 10% chance of "duplicate"?
In that way people will not save/load abuse it either. If you have the Potion of Luck and use save/load, and you find a RoLS while doing so (that didn't duplicate), it's not like you go "meeeeh, I only found one, I'll reload again"