I just received this question from an anonymous reader, and since it was a topic I was planning on writing a post about anyway, I'm answering the question here, rather than in the comments section of another post.
Here's the question:
Do you have any idea how many keys there are in total? I know I don't have them all but I am confused by the number of blank ones. Some of them I have I know are missing lithos but are there some that really are blank?
To answer your first question, there is one key per Precious Places set: 4 shops, 2 cottages, the Gazebo, the Mansion, 8 furniture sets, 6 outdoor scenes, 9 figures, and 4 mother & baby sets. That makes a total of 35 keys.
However, as far as I can tell, the Dining Room set was never sold to the public, so chances are you'll never get that key, which would make the number of available keys 34.
Of the 34 remaining sets, 28 definitely had key lithos. These are the 4 shops, 2 cottages, the Gazebo, the Canopy Bedroom, the Playroom, the 6 outdoor scenes, the 9 figures and the 4 mother and baby sets. (You can find pictures of some of the key lithos on my blog in other posts and more on ThisOldToy.com.)
That means that the sets that are not known to have had lithos are the remaining 5 furniture sets and the Magic Key Mansion. (To read my post discussing the furniture set lithos, please click here.)
Now why the Mansion wouldn't have a key litho is beyond me. It's the crowning jewel of the Precious Places village, was the most expensive set when it was sold in stores and clearly is the set with the biggest 'wow' factor. However, ThisOldToy has no picture of a litho, I've never seen a litho for it on eBay and both of the Mansions I personally own came to me with a plain pink key... thus I am sadly forced to conclude that the Magic Key Mansion's Magic Key didn't have a litho.
That said, I'm always happy to be wrong about things like this and if anyone has seen a key litho out there for the Magic Key Mansion, I would love to know about it. Please leave me a note in the comments section of this post.
So to summarize: as far as I can tell, there were 34 Precious Places sets (each with one key) that were sold to the public. To the best of my knowledge there are 28 different key lithos available, which means that there were 6 sets that came without a litho for the key. Hope this helps!