You can often purchase certain reasonable accommodation products such as colored overlays (to help those with dyslexia read the screen or printed materials more easily) and footstools from mainstream online stores like Amazon. Here is a useful guide to purchasing from Amazon when in Switzerland.
For more specialist items a specialist supplier is necessary.
Association for the Advancement of Assistive Technology in Europe
Among the activities of the AAATE is to help provide access to quality information on Assistive Technology and its provision across Europe.
Check out the Association for the Advancement of Assistive Technology in Europe website for more information.