Desmos does a really nice job of collaborating with teacher-users and making their activities better.
(Also, keep in mind that the Desmos Activity Builder isn’t a tool simply for math.)
Here are the different activities that I’ve created that have been enhanced with collaboration from the fine folks at Desmos.
Exploring Reflections in the Coordinate Plane
Polygraph: Square Root Functions
Partial Number Line Problem – Depending on your learning goals, this 3-Act could fit into an 8th grade, Alg I, Geometry, or Algebra II.
Pencil Sharpener Problem – Linear function problem that has been effective for exploration at the Algebra I and Algebra II Levels. Could be approachable by 8th graders, depending on the learning goals.
Please feel free to use these in your classroom. I look forward to feedback, experiences, anecdotes, and questions.
Mr. Shauver - Learner Educator 
I love your Exploring Reflections Desmos! I really like your use of the table to put the coordinates in and the types of questions you asked. I just tweaked the wording of some of the questions for my students. Thank you!
You are very welcome. I make them available for just this very reason. Also, good on you for tweaking it to make it work best for your students.
I hope your students learned lots!