Treasure Chests are chests that can be obtained in the Frontier via fishing in a body of water. Different treasure chests will reward players different tiered-rewards when opened in the player's inventory. These chests will give items based on the rarity of the treasure chest that the player has obtained. As of the 1.10 Update, there are 3 tiers of treasure chests that can be obtained in the Frontier.
Treasure chests may be obtainable by purchasing it from vendors. The only currently known treasure chest that can be purchased is the Deep Sea Treasure Chest. It can be purchased from Linkman the Junkman or Vhitmire. Linkman the Junkman sells the chest at a cheaper price of 3,200,000 gold, while Vhitmire sells the chest at a price of 3,400,000 gold. Treasure Chests may also be obtained from certain mobs, such as The Lost and the Red Ghost, or obtained from quests such as Giant Toad's Tasks.
Each treasure chest will reward players with various rewards based off on the tier of the treasure chest. For example, all of the possible rewards of the Treasure Chest will be below the List of Rewards (Treasure Chest), all of the possible rewards of the Grand Treasure Chest will be below the List of Rewards (Grand Treasure Chest), and so forth. If you would like to see the reward chances for the Deep Sea Treasure Chest, please click this link --> https://pastebin.com/edEuETpw. Unfortunately, we do not have the Treasure Chest nor the Grand Treasure Chest's percentages, however, you may refer to the Otherworld Tower rewards' pastebin list as a reference.
