As just a fellow user of both sites (non official answer), my interpretation of the policies and practices of both websites, Roll20 and YouTube, is yes, that would probably not be asked/complained for removal. It's you and your friends playing a game, which is within the expected uploadable contents of YouTube and Twitch.TV (a game streaming website that is being purchased by YouTube/Google, which has a Roll20 subsection and a D&D subsection). There may be qualifiers and exceptions to this, but generally, probably ok especially to the extent it's your own art & entirely your own creations. YouTube's policy for ads asks you to certify that you own all the rights to the creative parts of the video content (images, sounds). Could be getting more into sticky areas if you are broadcasting others' visual art and rebroadcasting sounds (thru Soundcloud jukebox), though in many cases the artist or sound creator would not be bothered by this use. It's clear that broadcasting Roll20's interface as part of your video is accepted. The sounds and visual images you put onto the Roll20 interface & choose to broadcast, that's up to you, and that is the area where you want to avoid broadcasting copyrighted materials that aren't licensed for this purpose. Example, you wouldn't want to upload Luke Skywalker copyrighted images into Roll20 and then record that for your channel. You should get permission from all your players/participants for something like this, ideally like a release signature for using their voice/likeness.
