See our Jamboard page.

Whiteboard.fi is a simple tool that can be used instantly. By creating a class and letting your students join, everyone will get a digital whiteboard. You as a teacher see all your students' whiteboards in real-time, so you can follow their progress. The students only see their own whiteboard and the teacher's.

Whiteboard.fi is an instant formative assessment tool for your classroom, providing you with live feedback and immediate overview over your students.

AWWapp (A Web Whiteboard)

https://awwapp.com/

AWWapp Education Blog

Whiteboard Fox

https://whiteboardfox.com/

Create a new board and paste its link in Google Classroom or send out via GoGuardian. 

Users will be anonymous, so you will need to be clear in your expectations regarding school-appropriate posts.

Ziteboard

Limitations - there is a limit on "traffic" so this is good for use with only a small number visitor.

Ziteboard is a web-based whiteboard with real-time collaboration!  For more info, see Ziteboard FAQ

Check out this lesson plan in which students create a collaborative study guide on their Chromebooks for their peers!

Create a Collaborative Study Guide

The best way to learn something is to teach it to someone else. For this activity, students who need to learn materials for an upcoming test will use the Ziteboard whiteboard extension to solve a math problem while recording their solution using the extension Screencastify.