Although it may sound somewhat morbid, gravestone inscriptions are an outstanding source of basic information on individuals. Even here, time has moved on and it is not necessary to roam around graveyards in search of dead ancestors.
The Billion Graves webpage is full of photos made by enthusiasts who have walked through the cemeteries and took the pictures of gravestones for us.
Prague cemeteries have a search application (and here). A similar tool also exists in Vienna.