Two overviews of funding sources and other important grants are available on this website:

The first offers a summary of the main options available (Swiss National Science Foundation, Latin universities, etc.).

The second, more especially designed for postdoctoral students, gives pointers for financing the development of the academic careers and mobility of researchers.

Mailing lists linked to scientific domains or specific institutions are excellent sources of information, both for doctoral and postdoctoral job vacancies and for academic posts. It is important to look for lists that are likely to be useful to yourself and consult them regularly.

Some universities publish their own guides to seeking funding (e.g. UNIGE). It may be worthwhile to consult them even for people enrolled elsewhere.

The EU Grants Access website also offers some useful information about availabilities of funding for Swiss researchers.

It is also a good idea to make enquiries personally about possibilities of grants offered by private foundations in your particular field.
Finally, word of mouth can also be a very useful source. Don’t hesitate to ask colleagues, professors, etc. for information.