I'm designing a learning environment where a student and tutor can have a learning session together.
I'm looking for inspirational/aspirational examples of really good collaborative workspaces that include components like tools and comms.
The software industry is a really good place to look because a lot of us work with remote teams.
I think invision has some cool things for collaboration - comment sharing and sharing of prototypes. If you thought of it as Power Point on Acid ... it could be a very cool education tool.
Slack is great in the ways it lets you organise groups of people and to share different media but I guess you are looking at 1 on 1
Some of the wire framing tools have collaborative options - they might be good because I guess sketching out ideas might be something students want to do. Balsamiq and some of the others - sharing screens on skype and codesigning an app with a colleague in Palo Alto (I am in the UK) using Balsamiq rates as one of my top collaborative experiences ever. Works best if you both have a pointer (which I seem to remember the web version of Balsamiq allows - if not it was another tool).
Then I would suggest co-authoring in all the Google apps is pretty amazing. For doing collaborative work across disparate groups it really is fantastic.
Then see if you can have a look at what some of the online schools are doing. The one I know well is Interhigh. I haven't seen their environment but they might be prepared to share it with you if they know you are studying these sorts of tools.
Hope that gives you a few ideas.