CastBuddy is, or at least was, a great free extension for the Google Chrome Web browser that allows you to stream video links from certain websites straight to your ChromeCast device.
This extension, however, stopped working after the last Chrome update sometime in September, 2018. And as of yet, there's been no fix, nor any input from the developer if or when it will be updated to work with the latest version.
You can still stream videos using the mirror option from the Chrome menu, but as you probably know this is intensive on your PCs resources and drains your battery in next to no time.
The good news is there are a couple of options you can still use which function in a very similar if not identical way to CastBuddy.
WebCast just like CastBuddy is a free extension for the Chrome web browser. This works in a near enough identical way, though it isn't as advanced or as fluid as CastBuddy.
Once you add the WebCast extension to Chrome, it will display a small icon in the top right-hand corner. Unlike CastBuddy, it won't detect the video link until you've actually clicked on the play icon on your chosen video.
Once you click on the icon, it will display one or more of the video URLs that you can click on. It will then open up a new page in the Chrome web browser and take you to a website called web-cast.appspot.com.
This page will display a video player, however, you don't have to play the video instead just click on the cast icon in the bottom right-hand corner. You'll then be prompted to choose your ChromeCast device and the video should then stream straight to your TV.
You can then close the Chrome browser, and the video will still continue playing via your ChromeCast.
Chromecast URL Player is a website where you can paste the video URL into the selected box and have it sent straight to your ChromeCast device. This isn't the easiest option, and you will need an extension such as Video DownloadHelper to extract the video URL from the video you want to stream.
To send a video to your ChromeCast device the process is very similar to WebCast. You'll need to find the video of your choice, click on the play icon and then extract the video URL by selecting the DownloadHelper icon in the top right-hand corner. If you put your mouse pointer over the title of the video this should reveal a little arrow on the right-hand side. Click on this and it will give you a drop-down menu where you can choose "Copy URL".
Once you have the video URL simply head over to Chromecast URL Player and paste it into the the box (number 3). You can then (number 2) connect to your ChromeCast device, and then finally select option number 4 to stream the video.
Remember, just like CastBuddy the above methods only work on certain video streaming websites.