One of my favorite youtube channels for teachers and educators is from Jarrod Robinson "Mr. Robbo the PE Geek" from down under. He is helpful, loves kids, and has a unique understanding of engaging bodily kinesthetic learners in all subjects and a passion for mobile learning.
A very useful livebinder by some teachers on QR codes in the elementary school with information and guides. I've found this is pretty updated even though the first page has a description from 2010. Very useful if you want to use them in your classroom or library at the elementary level.