Achieve is an independent, nonpartisan, nonprofit education reform organization. The EQuIP rubrics are designed specifically for the Common Core State Standards and units in mathematics and English language arts/literacy.
The NSDL is a great place to start a search for STEM materials across over 150 collections created by educators. Most items in this collection adhere to OER model, but some may be restricted to use by members of specific organizations.
All websites linked to EDSITEment have been reviewed for content, design, and educational impact in the classroom. They cover a wide range of humanities subjects, from American history to literature, world history and culture, language, art, and archaeology, and have been judged by humanities specialists to be of high intellectual quality.