Ephemera

1. Things that only exists for a short time
2. Collectibles, especially written and printed materials that were initially designed to be temporarily useful or important, such as tickets, posters, and etc.

• The word came from Greek: ephēmeros. Its singular form originally implies a plant that only lasts for one day, or an insect with a very short lifespan.

​Reference:

1. Merriam-Webster, s.v. "Ephemera," accessed June 15, 2019. https://www.merriam-webster.com/dictionary/ephemera.