There are so many resources out there for teachers if only you know where to look. But again; you will want to start small. When it comes to teaching resources, my two personal favorites are:
Pinterest is great because it connects to Facebook, and you can visually scan a page as you search for a specific term. Once you find what you want, materials are usually only a click away.
TeachersPayTeachers requires you to create an account, but provides a wealth of carefully curated materials. You can search by grade level, by content area, or by specific search terms. Besides just downloading materials (either for free or next-to-free), you can also upload yours–for free sharing, or charging a small price which would allow you to bring in some extra income because heaven knows you’ve got plenty of lesson plans, project rubrics, and curricula lying around!
Rubistar is specifically for finding or creating class rubrics. It is more limited in materials, obviously, but there is no sense reinventing the wheel when there are plenty of rubrics already created that can be downloaded for immediate use, or tweaked just a little before class tomorrow.