There are numerous sites online. Some have printable ideas for free. Here are a few links that I use a lot. I also have written many social stories on various topics. If you are looking for a social story about a certain topic message me and if I have what you are looking for I am happy to share!
Social Stories from Watson Institute
Speaking of Speech (go to Materials Exchange)
Autism Speaks Visual Supports Download
Lots of great ideas on Cindy's site
Autism Teaching Strategies Website
Pinterest also has lots of Visual Support Ideas. Just go to www.pinterest.com and search for the topic you are looking for or just search "autism visual supports".