Anything not sold yet by Xur would be the rarest. Assuming all drop rates are equal. PS exclusives win by technicality cuz they're not available to all Destiny players. Weapons not sold by Xur: Universal Remote Thunderlord Hardlight Monte Carlo Hawkmoon **4th Horseman** Vex **Nechrochasm** Armor not sold by Xur: **Arachnid Hunter helm** Heart of Praxic Fire Skull of Dire Ahamkara I think that's it, feel free and correct me. This info was checked with DestinyXur.com for accuracy. Items I have annotated by ** are items I believe to be the rarest, just for the fact that the expansion is new, 4th Horseman is PS exclusive, and a very small % of ppl have beaten HM Crota, let alone enough times to get a rare drop a lot of times from him.