! Hides video elements on Instagram that are not in stories
instagram.com##article video

! Hides most of youtube's recommendations (like shorts etc)
youtube.com##div#dismissible
youtube.com##ytd-reel-shelf-renderer

! Hides the "Watch Next" / suggested videos sidebar on the YouTube watch page
youtube.com##ytd-watch-next-secondary-results-renderer

! Hides the grid of video preview thumbnails shown when hovering or scrubbing in fullscreen
youtube.com##div.ytp-fullscreen-grid-stills-container

! Hides the YouTube comments section entirely
youtube.com##.ytd-comments