ADA is an American thing that sets a standard for disabled people (ex. Rules for wheelchair ramps, braile usage, accessibility of public spaces).

Japan has some broadly similar rules to help for example vision impared people, but most public spaces are still not friendly to those in wheelchairs, or with certain disabilities. I’ve seen elevators that are only accessible after you walk up some stairs, or train stations that simply have no working elevators.

• Octoprint if you have a 3D printer
• Volumio (or similar) if want a device you can cast music to
• for astronomy can install astroberry for remote control of your scope and camera
• run home assistant for home automation
• pihole for use as a DNS server that blocks ads
• plug a camera in and use it as a webcam/ security camera