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.
OpenBoard - The OpenBoard software is an interactive white board software.
Google Slides - Create a new presentation and edit it with others at the same time — from your computer, phone or tablet. Free with a Google account.
NoteBookCast - A real time shared whiteboard in your browser, teach, explain, sketch. For work, study, fun.
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.