During the development of the game, new items were gradually added to it, and even the familiar skins did not appear at once. Along with the usual items that can be traded, sold, there are more unique ones. They can be a reminder to the player of a unique achievement, participation in one of the operations, or time spent in the game. What are these items?
Items associated with majors and operations
Some items become rare because they are associated with time-limited events. In this category, for example, fall experience tokens that were given out during operations «Split Net» and «Broken Fang». They could be used to level up an account. Interestingly, if you didn't use the token until the next transaction, its design automatically changed, so it was pointless from a collection standpoint to try to keep it. The stars of operations are similarly organized. They could be used for rewards, but some players kept them to show off in their profile.
Souvenir tokens are similarly given out during the majors for completing spectator pass tasks. If you don't exchange them for rewards, they will stay in your inventory and just take up space, since you can't delete them either. However, some players prefer to keep such a token as a keepsake.
Cases, capsules, and keys called «Prototype»
The
average player is unlikely to have encountered items of this type, as Valve removed them from the game before they were fully implemented. It is not reliably even known what they were added for. Their mention was found in the game files, with the comment «Awarded for their contribution to the Steam Workshop». These cases may have actually been added for internal testing purposes. There is still a section for them on Steam, but they have never been bought or sold, nor can they be found in players' inventories.A similar fate befell the capsules «Prototype». Prototype EMS Katowice 2014 Prototype capsules were given to three players from the teams participating in the event. They cannot be exchanged or used, so they are still in the inventory.
Finally, the keys «Prototype» are given to the creators of the items «Workshop», which are in one of the cases. Such a key is distinguished from a regular key by a green box frame in the inventory. They also cannot be exchanged, so they simply serve as proof of its owner's accomplishments. After one of the unique key holders accidentally spent it, Valve removed that option as well. (And the careless owner received a duplicate item from the developers).
Trophies
Trophies – is another category of items not available to normal players. In full accordance with their name, they are issued to those who have participated in major professional championships. Awards go to the champions, finalists, and those who reached the semifinals or quarterfinals. You have to literally make the game your job to get to this level, so trophies remain the rarest and most prestigious items you can get in your inventory.