David Chartier, writing on Finer Things in Tech:

Apple tells you a number of things that iCloud syncs between devices in Settings (or System Preferences) > iCloud, such as Photos, Contacts, and Reminders. But I’ve noticed a number of other OS-level things that sync between my devices (presumably through iCloud), but Apple doesn’t seem to keep a central, comprehensive list. Let’s make one.

There’s actually several in here that I wasn’t aware of.