I love math, I love technology, and I love using technology to create learning activities and assessments. Below are some of the resources I use, some of which I've created or contributed to.
Desmos: Beautiful, Free Math
I've been using Desmos' online graphing calculator for years because of its beautiful, intuitive interface, low entry barrier, and ability to explore relationships between equations and graphs quickly. I learned about Desmos Classroom Activities at a workshop in 2016, and it changed the way I teach. This interface allows teachers to direct student exploration, see student work in real-time, and it's one of the best ways I've found to start in-depth classroom discussions. I started aligning my Desmos activities to the Common Core standards, and ended up throwing in activities from other creators as I used/reviewed them. This is a work in progress. You can view the spreadsheet here, and request editing access if you'd like to include your own activities, or other activities you come across.
GeoGebra: Powerful, Connected Math
GeoGebra's free online math software is another resource I've been using forever, and it just keeps getting better. With the addition of GeoGebra Groups in 2015, teachers can create classes, assign activities, and provide feedback. Groups have also allowed me the opportunity to work with educators around the world on the CCSS Tagging Project, which is aligning and tagging GeoGebra activities according to the Common Core Standards. Check out some of my activities, and some of the books I'm involved in, below.
Integrated Math 1-3 After a long time searching, I decided to base my G8-10 curriculum on the Mathematics Vision Project's (MVP) Secondary 1-3 curricula. These books are collections of GeoGebra activities made by me and others, and are far from complete. The sequence of units in these books is largely based on the sequence of units from MVP, and many of the activities are adaptations of those written by MVP. I also adapt a great deal from Illustrative Mathematics and EngageNY.