Elder Gelok's Supplies (Plane of Tranquility)
This quest isn't one that's required for Planar Progression and arguably isn't even a quest I would recommend you go out of your way to do. The only rewards for completing this quest are EXP (and not much EXP at that) as well as a chance of receiving a diamond/valuable gem.
What you have to do for this quest is extremely simple. All you need to do is bring some items that are found in the Plane of Innovation to Elder Gelok in Plane of Tranquility. Elder Gelok is found right next to the two cogs that you have to click on to zone into the Plane of Innovation. It honestly couldn't get any easier!
There's a total of four items that Elder Gelok is looking for, Tri-Platinum Foil, Mini-gyro Shields (rat-type enemies), Silicorrosive Grease (Uncommon zone drop) and finally Size 12 Sprockets (Enemies inside the factory). Every one of them is No Drop except for the Silicorrosive Grease which is both stackable and tradeable.
This single item is probably the sole reason I decided to include this quest. If you hand off a butt load of Silicorrosive Grease to a level 46 and they do the turn ins immediately after entering Plane of Tranquility - you might even get to see your EXP bar move a bit!