Created using Unity 2018.1
Create randomly generated dungeons from premade rooms by using only 3 components.
Copy the Assets/Scripts folder to somewhere inside your projects Assets folder. You may rename the folder to whatever you'd like. The prefabs and scenes folder are optional
Create a game object and add a MapGenerator component to it. Fill out the fields to your needs.
Next you need to create the rooms this generator can use. Create a game object that will be used as the room. Add a Room component and set the Bounds value which is used for the collision testing when trying to place a room. When editing the Bounds you should be able to see a Red rectangle based off it's values in the Scene View. Make sure the Bounds covers the whole room area.
Next your room needs X children with a RoomSpawn component. Move these children around to where the next room should spawn. The spawning works by aligning/connection the RoomSpawn spawns.
Once you have all your rooms created add them to the MapGenerator component. If you want a room to have a higher chance to appear you can add it multiple times.
To start the generation you just need to call the Generate() or Generate(int seed) function from the MapGenerator component.
I was too lazy to add in the hallways, to do this they should be separate meshes from the room and a child of the room (1 hallway per spawn point). Then just create a component that checks if it's related spawn point is connected to a room if it isn't hide it.