Greasy Fork is available in English.
11/14/19 - v23.0 'Add to' and other menu items work
02/03/19 - v21.0 fixed layout removing left-side whitespace
07/18/18 - v20.2 repaired 'add to..' (cheers to user Collin Chaffin for fix)
07/17/18 - v20.1 spf-remove quickfix
AboutAdds 2 links 'Newest videos' and 'Most Popular videos' (under the video player) that link to the current channel's uploaded videos pages - when clicked the page will be displayed in a dropdown sliding menu from the top of the page, so you can continue watching more videos without having to leave the page.
The dropdown page section is scrollable, to close simply click anywhere on bottom-half of screen.
(Note - Works on YouTube 2018+ site by bringing the old design back.)
YouTube's new material design updates break a lot of scripts, so this script integrates 'Get me Old Youtube' to get the old design (since YouTube removed the option), so then 'YouTube View More Uploader Videos' and other scripts can continue to work.
Get me Old Youtube: