Mine disappeared two days ago (I have about 60 Purchased/free apps).
The last thing I did was downloading the Infinty Blade II update. I needed to free up disk space (only had 1.2GB free on my 64GB iPad), so I deleted Monopoly. After the update I went to the Purchased tab in the App Store to reinstall Monopoly, and all the icons were gone. However, I was able to manually search for it and reinstall it.