List of youtube channels that also helped and inspired me:
FZDSCHOOL - More or less one of the most known concept art-related resources I know on youtube. It’s great to sit and draw and just listen to the talking.
SinixDesign- This guy is also great! He has some design workshops ever now and then where the viewers can send in their stuff for critique! very encouraging and inspiring!
moatddtutorials- This guy is more into drawing than painting, and has a more cartoony style. He has interesting methods when it comes to perspective. And he also challenge himself in some of his videos (the engine block video is a great example of this)
foxOrian- Also known here on dA for his awesome perspective and composition tutorials. He has a youtube channel where he posts some videos that might be interesting as well.