You will not always find them, their frequency appears from 0 to 1 in large Reward Boxes.
Even so, you can receive other objects that will serve you for different instances.
You can also go to the Iron Gauntlet to get a Tournament Crate and thus get epic items thanks to the Gauntlet Coins.
You can get Gauntlet Coins even by watching ads, as well as daily you will have the chance to withdraw rewards to improve your weapons and equipment.
Even so, you can receive other objects that will serve you for different instances.
You can also go to the Iron Gauntlet to get a Tournament Crate and thus get epic items thanks to the Gauntlet Coins.
You can get Gauntlet Coins even by watching ads, as well as daily you will have the chance to withdraw rewards to improve your weapons and equipment.