The Arc is an advocacy organization for people with Intellectual and Developmental Disabilities (IDD). It emphasizes the individuality and agency of people with IDD and as such prioritizes the voices of people with IDD and their families when making decisions. True to this mission, their board includes people with IDD and their loved ones.
The NCLD is a research and advocacy group for the 1 in 5 children with learning and attention issues. It gives out scholarships and also has initiatives for young adults ages 18-26. The board of directors includes parents of individuals with learning disabilities and individuals who have learning disabilities themselves.
This site is from the University of Michigan, but it's open-access. It provides resources for parents, teachers, and dyslexics. It's unclear what role, if any, dyslexic people had in its creation or its content.
This is a group of professionals committed to enhancing postsecondary access for students with disabilities. If you see yourself in an EEO/Disability Resource professional working in Higher Education in the future (or are one currently), this is a group you may be interested in.