Instead of making folks ferret out multiple posts for apps info, I've put together a categorized spreadsheet of iPad apps for autistic people -- the ones that work for Leo, yes, but eventually lots of other apps as well.
If you have any suggestions or questions, let me know.
UPDATE 1/24: The spreadsheet will include reviews and recommendations from Corina Becker of The Autistic Adult App Project and No Stereotypes Here, and Jordan Sadler, SLP of Communication Therapy.
UPDATE 5/2017: I am no longer updating the spreadsheet, but am leaving this page here as an archive resource.