Ačiu super veikia :)

Yes it's still only 4 videos per roll but it's nice to not see overblown reaction thumbnails in hd when I'm going to ignore them anyway

Reduces thumbnail size but only shows 4 videos per row instead of 6, so there is a large amount of unused white space.

Unfortunately, this addon no longer works. YouTube still shows 4 thumbnails. Perhaps something changed in YouTube after all this time.

thank you so much, I had a mini-panic attack thinking I had lost this extension after switching from chrome. You are a legend!

For the search results try to install stylish. Create a new style using this:
ytd-video-renderer [use-prominent-thumbs] ytd-thumbnail.ytd-video-renderer {
margin-right: 16px;
max-width: 36px;
min-width: 220px;
-ms-flex: 1 1 1e-9px;
-webkit-flex: 1;
flex: 1;
-webkit-flex-basis: 1e-9px;
flex-basis: 1e-9px;
Just copy and paste. It is not perfect but it is better than these giant thumbs.

Works on homepage, but does not include search results. :-(

Good

Does what it says, No more super-sized thumbnails.