Loot boxes, or other variations of the same idea are a package of random items. These items often consist of cosmetic items or cards.
Some games, such as Overwatch allow players to purchase loot boxes as well as earn them by leveling up in the game. Other games, such as Counter-Strike: Global Offensive and Team Fortress 2 give players the crates for free while playing the game, but require that keys be purchased to open them.
Many online focused card based games feature random card packs that work essentially in the same manner as a loot box. Games like Hearthstone, Pokemon Trading Card Game Online, and even the Madden series feature purchasable random card packs.
The use of loot boxes has cause quite a stir in the gaming community with critics equivocating the distribution of randomized digital items akin to online gambling. Companies who use this approach by allowing users to purchase loot boxes have come under fire from different countries who have restricted or regulated gambling laws.