Disabling autoplay for Twitch channels on the homepage

I've fixed this by adding the uBlock Origin add-on to my browser.

Install it and:
1- Go to the page featuring the content(s) you want to block;
2- Right click on that page (important: on the page, not on the frame you want to block);
3- Select "Block Element";
4- Select the frame you want to block;
5- Select "Create" = Boom: frame gone;

Here's a video of the whole process.

Thank me later :P