Blizzard has clarified the full list of legendary items that can *only* be obtained by playing in Season Three. (Until the season ends and they join the general item pool.) Season Three Exclusive Legendary Items:
Instantly restores 60% Life. Increases healing from all sources by 20-25% for 5 seconds.
As with previously reworked Seasonal items, once patch 2.2.0 launches, these items will no longer drop in non-Seasonal games and will remain removed from the non-Seasonal Legendary pool until Season 3 concludes.
The common player complaint is that some of the non-seasonal new or changed Item Sets aren’t as useful without certain legendary items that pair ideally with the, such as Dead Man’s Legacy with the new Multishot Unhallowed Essence set, or the Ob/Zod with lots of things. There’s no real response to that other than, “play seasons, Dude.”
We know from the Tavern Talk that S3 and future seasons should run for about 3+ months, so if you refuse to Season your heroes, at least you won’t have to wait much past the start of July to get your shot at these S3 exclusives.