During the current incarnation of the course in Hamiltonian Mechanics I have collected some amount of material to share with the students. To avoid losing it in the guts of our teaching CMS, I leave it here for posterity, practically copy-pasting it without edits because I am really tired :D

The books on SpringerLinks linked below are accessible from our students for free via the university proxy but in general (unfortunately) not open access.

Additional material (also linked in the lecture notes):

Extra material on similar topics

Some courses that touch on similar concepts, often from different point of views:

Further material for the projects and extra lectures

In addition to the material added above (lots of it is not open access unfortunately).

A spotted animal homeomorphic to a sphere - Wikimedia

Meeting (virtually) with your peers

To meet with your peers you can use, for example, the free and open solutions Jitsi meet and Jami. For small groups you could also setup a Gather Town or a Wonder room.

For mathematics, it is enormously useful to be able to share computations and drawings. To this end you may use your webcams, mobile phones as webcams (there are plenty of good free apps for that), tablets with collaborative whiteboards, …

If you want to do fancy stuff with change of scenes and interactive polls, like the one done by 3blue1brown with itempool, you can spend some time playing with OBS Studio.

For what concerns collaborative whiteboards I have tried the following, and they all seem to work fine (each has its pros and cons, so I list them all): microsoft whiteboard, google, ziteboard, whiteboard and Explain Everything.

For editing mathematics online collaboratively I usually use latex and the overleaf online editor or HackMD. I don’t know if it is collaborative, but I have many colleagues that praised Mathcha, and I also recently heard of Math Whiteboard, which is both free and collaborative.