I like this particular blog post about being confident in teaching improvisation. It breaks down some great ideas for keeping everyone engaged and growing.
Great resource for all subject matters. It also keeps a library of all your purchases in case you lose them. All lessons I have bought through here have been of very good quality and easy to use.
This website has hundreds of great resources for elementary education and often includes great lesson ideas. Faeries and Giants is one of my favorites to do with 4k when learning highs and lows
Bucket drumming is a favorite activity during rhythm units in just about any grade. Coach K makes this whole process easy and encourages us to share our experiences.