D2L is a Learning Management System (LMS) that we here at OSU know quite well thanks to the Online Classroom. It is a great way to connect all of your students into the class. You can do online quizzes, synchronous communication, asynchronous communication, upload syllabi and other content, etc.
This is a website that provides teachers with a way to find and/or create lesson plans. It has many great links for grades K-12 as well as links for professional development and parents.