Parents of HN, what are your favorite learning apps?

I am a teacher and startup founder. I'm currently leading 4 digital learning pods for kids Prek, lower elementary, upper elementary, middle school and high school. Most of our pod time is focused on social-emotional learning and collaborative projects. We've found it's been really effective for students to supplement their class time with independent study using fun mastery-based learning apps. So far, we love math tango, animal typing lite, teach your monster to read, writing wizard, khan app kids. Would love some other recommendations for math, science, language arts, music, creative writing (and especially apps for older kids).

What are some other apps your kids love for independent learning?