This website has worksheets for grade-school math through high-school math, as well as critical thinking--something we all want our students to do. There is a search bar if you're looking for a particular topic and want a break from textbook problems!
This has links to different lesson plans for pre-algebra, algebra, and geometry. These are free to be viewed online, as opposed to a book that you have to buy from them.
These are the Illinois State Standards for what students should be able to accomplish in mathematics classrooms. It has some relation to the NCTM Standards that we covered in CI 401.