With the weekly reset, the final step of Tyr's questline is now available, beginning with Retrieving the Disc and ending with exclusive rewards… though perhaps not the ones we expected!
We last left off the quest to reforge the keeper Tyr in 10.1.7, in which we helped recreate the Tyr's Guard and received the Dragon Isles Drakes: Gilded Armor as a rewards. The Tyr's Guard now prepares to journey to Suramar where Tyr's Disc is being held in a timeline where the Nighthold is still controlled by Elisande.
Although believed to award the long awaited Dragon Isles Drakes: White Scales dragonriding customization, that does not seem to be the case, as completing the actual questline seems to only award the Of the Tyr's Guard title and achievement. Datamined without a source during the Patch 10.1.7 PTR, Blizzard later confirmed that customization would be rewarded from Tyr's questline in Patch 10.2… although so far that does not appear to be the case, leaving it unclear where the scales will actually be obtained from.
Also interesting is the still undiscovered Tabard of the Tyr's Guard, which also seems like it «should» be a reward from finishing the lengthy questline, although it is possible that it will be an exclusive reward for Paladins or perhaps another follow-on step that has yet to be discovered.
Like the white scales customization, the tabard still remains undiscovered.