You can look at RCI as a non member and get an idea. It's around 500 (less than 10%) of the top RCI resorts excluding Orlando. The Disney collection is the Disney hotels excluding value that don't have a
DVC component plus
DCL. Then there's adventures by Disney. In addition there are direct trades with Club Intrawest and Club Cordial but not all of their resorts. Finally there are a handful of high profile resorts (12 currently) such as the Del Coronado and Grand Wailea.
Realize that these exchange options could change or evaporate tomorrow, are a very expensive and risky use of DVC points and it is an extremely poor choice to buy expecting to use them. You're far better off ($$ and otherwise) to buy just the points you'd use at DVC with a small cushion (?10%) and looking at other means (cash, other timeshares) for the other options.