Are there rewards for exploration?
Heart merchants have a number of armor and weapon skins not available anywhere else. Champ bags have weapon skins only found there.
I not sure how there could be unique skins in a hidden spot somewhere that hasn’t been found by at least one person after almost 3 years so I’ll say no to that.
ANet may give it to you.
I don’t mean items that no one else has found, I simply mean items that can only be gotten by exploring. Unique skins/armor/weapons that can be discovered in game.
There are a few skins that can only be obtained from karma vendors (via direct purchase or recipes) and a lot of chef-crafted foods that require supplies from such vendors.
There are several unique items that only drop from certain bosses, including many of the world bosses, Orrian temple bosses, and local bosses (e.g. Rhendak).
If OP means something like exploring a cave and finding a chest that has a unique skin, then no. That would be impossible to do with an mmo imo. If in the same spot, then it can’t remain unknown. If it spawned “randomly” it would still spawn at set points. It wouldn’t take long for this to be worked out and posted on wiki so that everyone would run to its spawn point for their daily chest opening.
ANet may give it to you.