Türbe's or mausolea are all over town. Many will be closed for several reasons. One of them is to prevent theft and wanton destruction. Because they tend to be treasure troves: the better ones will have Iznik tiles that are a treat by themselves, some are by the best architects. So whenever I find them opened I enter and if possible take pictures. As I am reorganizing I now group them for as much as I can. Most will be of sultans, but some vezirs, pasha's or holy man had tombs made that deserve to be placed here. I hope to extend the collection: some were closed for restoration. Also I hope to find some loose ones in my somewhat overloaded collection.
There is an organization that seems to be founded for the upkeep and display of türbe's. Its website has some fine examples of what it may grow into, however, I have the strong sense they suffer from a lack of money, because prominently "WE ARE WAITING FOR YOUR DONATION" and a bank account are given. It is in Turkish, but you just try what works. Some displays are "3D".