I'm going to assume you mean the Home app "icon". If so, it's probably hidden in a folder on one of your home screens. If not, you can always restore your device to bring it back. Also, if you haven't removed the Home app from your device, resetting all settings may cause it to reappear.
If it was deleted by mistake, go to the App Store and download it back.
I couldn't find my iCloud Drive app. On a hunch, I searched it in the App Store, and sure enough, there it was ready for download.