Gold for riding training. Travel time is a SIGNIFICANT time sink while using quests to level. You don't want to wait to get it. In fact, while questing, the second you ding 40/60/70/80 you'll want to hearth and train it IMMEDIATELY! 10304 gold is the base cost, which will be modified by reputation. Also, make sure you're in a guild with the 10% riding speed bonus unless you're a class that already gets a mount-speed buff.
Chilled to the Bone, Dampened Magic, Kleptomania, Netherwind Armor, Prismatic Cloak, and Temporal Shield have limited use in PvE content in terms of increasing your damage in the open world, but they can be situationally useful. Notably Temporal Shield can be utilized for, functionally, an extra 6 seconds of combat time against large elite mobs.