Invidio.us is a website, based on the Invidious software, that functions as a ethical alternative front-end for YouTube. Unfortunately the front-end of Invidio.us is going to shut-down on September 1th. Luckily the lead developer of Invidious, Omar Roth, made the software free and open source. Already a number of other website with Invidious exists. Here is a link to the list of other instances: https://instances.invidio.us/.

For those interested, here is a link to the blog post of explaining his decision: https://omar.yt/posts/stepping-away-from-open-source