For retail, the planogram stuff is really cool. Personally, there're so many charts I think could be utilized more but of the more accessible ones, my favorites are dumbbell/slope charts, as well as bump charts and even just good old bullet graphs. If you wanted just a great overview of charts, I'd check out the following public pages:
If you wanted to just see some crazy things people have done with Tableau, here're some of my personal favorite authors:
As for visual best practices/design, there're some great resources on our website / leanings pages (see here). You could also find a ton from our YouTube page from conference last year:
Hope that helps.