Here's a very useful and highly rated teaching resource website known as Teacherspayteachers
It's created by teachers for teachers and features a wide collection of both free and paid resources for all subjects and K-12 levels. Basically, it is an online marketplace for buying and selling of original downloadable educational materials.
I have personally purchased the Grammar Comics Parts of Speech series from David Rickert for USD8.99 in 2011. It presents parts of speech exercises in a fun and amusing way through comics. It is a great collection to add to my Grammar lessons. He also has a wide repertoire of Comics exercises on Poetry, Metaphors, Irony, and even Maths Fractions. You may also want to check his website at http://www.grammarmancomic.com/rickert.html
Here's a great free resource to affirm students positively - Happy Notes. It is a good take home resource to show parents positive behaviour of students. Rather than send parents reminders about lost and incomplete assignments, why not use this instead?