Google promotes some popular iOS and Android apps on its home page
Android apps listed include the Chrome Browser, Google Maps, Google Photos, Google Translate, and of course, YouTube. Others include Snapseed, Gmail, Hangouts and Google Drive. Many of these are already pre-installed on a new Android phone.
If you click on the iOS link, you will receive a number of pages for both the iPhone and the iPad. If you got a new iOS device for the holidays, you are going to want to install some Google apps. For example, remember that the YouTube client hasn't come pre-installed on iOS for years; that is a must-have that you will want to download on your new iOS flavored phone or tablet right away.
source: Google via MobileSyrup