Unstable Arcanocrystal
The Unstable Arcanocrystal was one of blizzards hilariously over-budget trinkets similar to the Everburning Candle in WoD. This sumbitch was so op that you'd use it over pretty much every other trinket that wasn't like 40+ ilvl higher (yea, most of the trinkets in Legion were pretty shitty).
Another defining feature of this trinket is that it was pretty much impossible to get on your main. It dropped off Withered J'im one of the random weekly world bosses in Legion that could go months at a time without spawning.
Gambling Addiction
Patch 7.2
When 7.2 hit, Blizzard added a vendor to the Broken Shore where players could exchange 5000(not 4986) Nethershards gathered from mobs and quests in return for a token of their choice of any equipment slot. This token could roll into pretty much any item in the game, including an Arcanocrystal. The base item level for this was 880.
Patch 7.3
The same concept as in the previous patch, the vendor had moved from the Broken Shore now onto the Vindicaar on Argus. The currency was changed because Blizzard didn't want players to stockpile nethershards since now the base item level for the tokens was 910. The 30 item level boost only fueled players gambling addictions even more.
