There are lots of activity managers and to-do list-type products but none of them is built for teachers. They are built upon teams and projects, whereas in classes, each student is a “project” in and of itself. Moreover, the project activities for each student/project are mostly the same. For example, a teacher may have 5 classes of 20 students for a total of 100 students. The teacher would probably assign the same homework to most students with a few exceptions for students that are moving faster/slower than others.
Create an add-on where teachers can bulk-create tasks and assign them to classes or groups of students. Create a dashboard so that teachers can see incomplete tasks easily.
I reviewed about 30 applications and nothing product supports students this way unless I write code to make API calls. Just my $0.02.