Chrome Extension:
https://chrome.google.com/webstore/detail/udemy-faster-autoplay/fepcpdjalebcocminbnogcgfbphllkeh
Firefox Add-on:
https://addons.mozilla.org/en-US/firefox/addon/udemy-faster-autoplay/
If you enable autoplay while watching a Udemy playlist, once a video ends, you are usually advanced to the next video after a 3-second delay. This extension removes that 3-second delay so that you are always advanced to the next video immediately.