Differences between fellowships in Europe From the perspective of a young postdoc career in Europe, what are the differences between applying to a Marie-Curie, a Humboldt (in Germany), or an Emmy Noether fellowships?

Bonus question: Are there other fellowships other than the three listed above?
I am assuming you mean the Humboldt postdoctoral fellowships, since the Humboldt foundation has many different funding programs. Each of these programs all have their own application procedures and eligibility criteria, so you should read the respective application guides carefully and keep track of the different deadlines, if applicable. For example, the Humboldt and Emmy Noether fellowships have to be taken up in Germany, while the Marie Curie fellowships are EU-wide (well, it's slightly more complicated than that).

The main component of all of these applications is a research proposal, but each of them require different formats. For example, for the Marie Curie applications they provide a template describing all the sections that should be in your proposal. 

The Emmy Noether fellowships differ from the others in the sense that they allow you to become a junior research group leader, i.e. they also provide funding for some PhD students and postdocs. You have to have at least two years of experience since your PhD to apply for a Emmy Noether (but not more than four). Because the amount funded is larger, I think the Emmy Noether is regarderd as the most prestigious of these fellowships (and presumably also the most difficult to obtain).

Finally, for your bonus question: yes, there are certainly many more fellowships, some field dependent, but for Germany specifically I think these are the most important individual fellowships.