After Effects Tutorials:
www.adobe.com/support/aftereffects
https://mattrunks.com/en/tutorials/free
Lynda:
After Effects: Creating a Mobile App Interface
https://www.lynda.com/After-Effects-tutorials/After-Effects-CC-Essential-Training-2015/371399-2.html
Skillshare:
https://www.skillshare.com/classes/design/Animating-With-Ease-in-After-Effects/2128437497
Motion Design Tutorials: