Here's something that isn't on the list but I've made my first remote working experience with it:
- MOOCs (Massive Open Online Courses)
I don't know whether this is a stable advice, but if you're into learning things and appreciate the fact that teaching others has a great learning effect in itself, then considering to become a part-time teaching assistant or forum mentor for courses that you know stuff about and are interested in might be a way to go : )
There are quite a lot of MOOCs providers out there by now, you can check out [edX](https://www.edx.org/
) and [Udacity](https://www.udacity.com/
), to mention the ones I am most familiar with.
I can't really give you a failsafe way to get into such a position, but I guess working through a course that really interests you and showing your excitement, knowledge, and willingness to help out in the forums is a good way to start. : )
And then there's also the possibility to just *teach a course yourself* - [Udemy](https://teach.udemy.com/?ref=teach_header
) offers this possibility and although I have no experience doing this, I imagine that it can be a great way to share some exciting knowledge you may have and earn money from people who appreciate it!