Stylus

Stylus is a Chrome extension for managing user styles (as in, CSS stylesheets).

Links:

• Chrome Web Store: Stylus
• Source code

YouTube

A stylesheet to disable recommended videos on YouTube:

.ytp-endscreen-content,
ytd-watch-next-secondary-results-renderer,
ytd-two-column-browse-results-renderer[page-subtype="home"]
{
    display: none;
}