One of my favorite weekly rituals is running around the Isle of Thunder finding my Trove of the Thunder King for the week. It's not even really the contents that appeal to me - woo, more ritual stones and Elder Charms - but just the thrill of the hunt, of finding TREASURE.
Over the last few weeks, I tend to check certain areas more than others where I've had repeat success finding chests. Here's some of my favorite locations.
Outside the Lightning Mine, by Backbreaker Uru
This is the only chest location that's running 100% success for me. It's all the way through the Lightning Vein Mine, out back by the big statue. It makes sense why this one is always around, given what a huge pain in the ass fighting through the mine can be. But you can reach this back area very easily by swimming up the coast to reach it - it's a short swim, or you could obviously use Water Walking, Path of Frost or a Water Strider mount to make the trip even faster.
Just inside the back entrance to the Lightning Mine
Did you just check for the chest mentioned above, and find nothing? Well, turn around and take a few steps into the mine. I've found this chest multiple times, probably for the same reason as its outside neighbor - who goes into the Lightning Vein Mine if they can help it? Especially all the way through to the back.
Central temple, facing the Shado-Pan Assault cave
I'm always surprised when this chest is up, considering how open and exposed it is and how many players travel right past it, running from the Shado-Pan Assault cave to elsewhere on the Isle. I've gotten this one or shared it with guildies numerous times.
Central temple, facing the Alliance area
As above, only around the side.
In a tree between the Shado-Pan den & Court of Bones
Easily missed, and easy to check on.
Ihgaluk Crag cul-de-sac
It blows my mind that this chest is ever up, since it's in such a heavily-populated area and is absolutely out in the open...but I've found it a few times now. I'm always paranoid about killing those two nearby Saurok first, in case I go to open the chest and they aggro/attack me, making the chest despawn without actually receiving the loot.
Ihgaluk Crag, random caves
Ihgaluk Crag is by far my favorite place to look for chests, since you can just leap and bounce around freely without worrying about aggroing anything. Also, it's fun. The caves, which serve no real questing purpose, can be a nice place to look for chests since not many people actually venture inside.
Western Zandalari dino pit area
This chest isn't great. It's in a heavily congested area where you'll likely aggro a bunch of raptors and/or trolls, and this particular tent is guarded by a mean Dinomancer AND Loa-Infused Bloodhorn. (It's the one used for the Direhorn in a China Shop achievement, actually.) However, the chest is well-hidden and it'll probably be there, if you've tried your other favorite spots and had no luck.
Just watch out for respawns!