I was looking through the worlds on the exchange the other day and I stumbled upon a world by Rflong7 called "A Tiny Town." It has around 30 empty 10x10 lots and a few slightly larger ones, 10x15 and a few 20x20 ones. Most of the common rabbit holes are there too.
So, I got all the tiny builds here downloaded (as long as I was sure there was no CC attached) and some I had made in the past and almost filled it up.
I'm going to do a little walk through and I'll post some pictures of it in a few days, It's adorable and tiny :)
PS here's the link to the world -> https://www.thesims3.com/assetDetail.html?assetId=5489542