Not sure, but have seen the Jellyhorn drop for a few weeks in a row to someone in one of my Nightfall groups (never me of course). My son barely plays at all and the one Nightfall he did do naturally got him the 'Horn. I helped a guy 2 levels below Nightfall level finish it after I had done it on my 3 'toons and he got a Hawkmoon for it and has gotten a couple more since. Doing Nightfalls isn't enough, you probably need to be doing as many raids or high level events as possible so you have as many lotto tickets as possible. I never bought Red Death or got the Monte Carlo, Thunderlord or 4th Horseman drop, but am more interested in the ones that I would likely use the most.