YouTube First Playlist Video for Chrome
More About YouTube First Playlist Video
This extension gives different options to open only the first video of a YouTube playlist. To open it, the user has to right click on the thumbnail or the title of a playlist and click on the extension's context menu option (take a look at the first screenshot). In the settings page (that can be accessed by clicking on the extension's icon), there can be found six different ways to perform this action and only one can be chosen from among them.
The context menu item only appears when right clicking on playlists on YouTube, and it is not shown in any other place.
FYI: Extensions are not activated automatically when they are installed. This extension, like many others you have tried probably, starts working on all the corresponding tabs at the right moment it is installed, but this is not the default behaviour. Take in mind that if you install an extension sometime and it doesn't work on the tabs you have already open, you may need to refresh those tabs with F5 key or by clicking on the reload button located in the browser's top left corner.