RandPlay Bookmark is a free Chrome add-on developed by mathric. It falls under the category of Browsers and specifically the subcategory of Add-ons & Tools. This handy tool allows you to randomly play YouTube videos from your bookmarks continuously in the background.

With RandPlay Bookmark, you can select which folder of bookmarks you want to play from the option page. Once you have made your selection, simply click on the RandPlay Bookmark icon and you're good to go! The add-on will automatically switch to a new tab for a few seconds to trigger auto play, and then switch back. After this initial setup, you won't need to switch tabs again.

It's worth noting that if you have other YouTube extensions installed, you should ensure that they do not stop the video play in the background tab if you want them to play continuously. RandPlay Bookmark provides a convenient way to enjoy your bookmarked YouTube videos in a random order, making it a great tool for discovering new content.