O.k. this one is probably obvious to anyone looking at my site. And it should be! Teachers Pay Teachers has a number of excellent materials for free as well as for sale. It's even a great site just for getting ideas!
This is a one-stop-shop for most things musical. They have a huge catalog of printed music resources as well as instruments, methods and training materials. They are fast and reliable.
I have found some amazingly useful images and creative ideas on this site. Elementary music teachers often need to get crafty. But why re-invent the Recorder Rack when you can find ample pictures and multiple ways to put them together here? Also, sometimes teachers just need to look at pictures of cats.