One charity that I support is called
World Bicycle Relief. It provides bicycles to people in Africa (healthcare workers, school age girls, farmers, etc) to allow them to expand what they can do and to try to keep girls in school. It also trains mechanics to fix those bikes. Given how much biking has enhanced my life, I highly support providing bicycles to people who can't afford them. Here is
an article I wrote about them.
Obviously, this has nothing to do with bike touring, but I feel it is a worthwhile cause.
I also became a life member to the ACA several years ago as I support what they are doing 100%. I also donate to warmshowers.org.