I am wondering the same thing. I am in the process of creating a button add-in from a script, and I could sure use some samples.
Are you wanting these added to ArcGIS Online? Or Desktop? If Desktop, there are some sources....didn't know you could for the Online. If for desktop, you might want to move the post to one of the developer locations I cross posted to below.
cross-posting Python AddIns python snippets Python Developers