I simply cannot understand how YT recommends content for me to watch. Gender reveals, cartoons, football, kardsah!an clan, channels in a foreign language... aargh! Most irritating to scroll through the suggested videos.

And YT itself does honor my choosing not to see these channels anymore.

Well, this extension is the best one I have tried that manages to block suggested channels. I have blocked multiple channel by name, blocked by keywords, and happily report that there is no noticeable slowdown. Most importantly, YT is now watchable again. Well done to the developer, a 5 star rating is deserved.