Common Core Problem Based Curriculum Maps - Geoff Krall of Emergent Math has organized thousands of problem based tasks. He has sorted them by grade level, Common Core standard, and subject. Seriously, so much good stuff that my mind explodes every time I visit the page.
Desmos Activities - Interesting activities that are ready to use in your classroom. Until recently there were only a few activities posted, all of high quality of course. Lately however, new activities are being posted more often. Yay!
The Math Projects Journal Lessons/Curriculum Maps - Chris Shore has organized projects for middle school and high school. He has included both and Algebra 1, Geometry, Algebra 2 sequence as well as an integrated sequence.
Robert Kaplinsky's Lessons - Robert has complete lessons that teachers can use without spending hours collecting media resources and data (because he has already done it for you). Most lessons start with a situation and the statement of a problem. Robert includes tons of images, videos, desmos graphs, questions to ask,... everything you could possibly ask for.
And last but not least, virtual filing cabinets like Sam Shah's. Virtual filing cabinets care exactly what they sound like. Typically they are one page on someone's blog where they organize all of the lessons that they teach by sequence and include links to resources that they use for each lesson. I chose to link Sam's virtual filing cabinet because his "top drawer" is a list of other people's cabinets!