AVID:Requests for Comment/Introduce endcards
From the Audiovisual Identity Database, the motion graphics museum
Introduce endcards
I say that we should include endcards from YouTube videos in this database. They obviously cover both halves of the criteria for the wiki ("audio" and "visual"), and some also have logos - a similar case with film leaders where a few of those contain them. Two examples of this are: https://postimg.cc/PLwbsX66 https://postimg.cc/7fzq2jQF
There's that for you. In terms of what section they would go under, they'd probably be most fitting in the miscellaneous section. Also, YouTube notability guidelines apply of course.