There are several other applications similar to Teacherbot that are available for free. Some popular options include:

1. Google Classroom: This is a free web service developed by Google for schools that aims to simplify creating, distributing, and grading assignments in a paperless way.

2. Edmodo: Edmodo is a free online platform that provides a safe and easy way for teachers to connect and collaborate with students and parents. It offers features such as assignment management, communication tools, and a library of educational resources.

3. Schoology: Schoology is a free learning management system that allows teachers to create, manage, and share content and resources with their students. It also offers features like online assessments, discussion boards, and gradebook management.

4. Canvas: Canvas is a free learning management system that provides tools for teachers to create and deliver online courses. It offers features such as assignment management, grading, and communication tools.

5. Moodle: Moodle is a free open-source learning management system that allows teachers to create online courses and manage student activities. It offers features like assignment management, discussion forums, and online quizzes.

These applications provide similar functionalities to Teacherbot and can be used by teachers to enhance their teaching and communication with students.