In today's Patch 10.1.5 PTR build, new Quantum items were added which provides Transmog appearances (from the Past). It's unclear how players will acquire this items and also what type of appearances this will drop. Some initial questions would be:
Will players be able to get any item from the past? Will this include popular old sets like Tier 3 and the Challenge Mode sets? Will this pull from only a set amount of transmogs? Quantum Items in Patch 10.1.5Here are a list of the Quantum items in Patch 10.1.5 which awards some kind of appearances (from the Past).
Quantum Crossbow Quantum Mace Quantum Axe Quantum Greatsword Quantum Greataxe Quantum Greathammer Quantum Staff Quantum Polearm Quantum Bow Quantum Sword Quantum Firearm Quantum Knife Quantum Knuckles Quantum Warglaives Quantum Wand Quantum Focus Quantum Shield Quantum Headpiece Quantum Chestpiece Quantum Legs Quantum Gloves Quantum Shoulders Read more on wowhead.com