Scribblar - Scribblar is a free online collaboration tool that is perfect for online tutoring.
Prezi - Welcome to Prezi, the presentation software that uses motion, zoom, and spatial relationships to bring your ideas to life and make you a great presenter.
IDroo - A shared whiteboard for use by multiple Skype-users simultaneously. Features
Keynote - Keynote for Mac, iOS, and iCloud lets you make dazzling presentations. Anyone can collaborate — even on a PC. And it’s compatible with Apple Pencil.
OpenBoard - The OpenBoard software is an interactive white board software.
Microsoft PowerPoint - Microsoft PowerPoint empowers you to create clean slideshow presentations and intricate pitch decks and gives you a powerful presentation maker to tell your story.