I am collecting lesson resources and task resources. I differentiate them by including full lessons in the lesson resources and tasks that require lessons in the task category.
MARS – This is great collection of lessons (they call them FALs) and tasks as well.
Yummy Math – They create great lessons based on deep tasks.
NRICH – Nice collection of materials grouped for quick discovery of tasks related to what I am looking for. Note: Given that this is a site based out of the United Kingdom, the filters are slightly different.
Mathalicious – Great lessons that are mostly middle school and growing into high school.