YouTube has recently launched Sponsored Cards, which is a new ad-format. YouTube states:
Sponsored cards display content that may be relevant to your video, such as products featured in the video.
Viewers will see a teaser for the card for a few seconds. They can also click the icon in the top right corner of the video to browse the cards.
You don’t need to do anything to receive the benefits of sponsored cards, YouTube will automatically enable cards on monetised videos. This is a new way for rights holders to make additional income, and is available on mobile, where over 50% of all views are now coming from.