activsync from Outlook.com http://thunderbirdtweaks.blogspot.com.au/2014/10/sync-hotmailoutlookcom-contacts-with.html

CardDav (includes icloud)? using the sogo connector http://www.sogo.nu/english/downloads/frontends.html

This link http://www.dummies.com/how-to/content/how-to-sync-address-book-contacts-with-your-iphone.html says iPhone will sync natively with Windows contact. If that is true then these instructions http://thunderbirdtweaks.blogspot.com.au/2013/12/windows-contacts.html will incorporate Windows contacts into Thunderbird a an additional address book.

Matt,

None of these seem to be able to sync Thunderbird's Address book with the Contacts function native to the iPhone.

sync it a rtwo part process. you sync your phone to something and then sync the something to Thunderbird.

The graphic on the page at dummies.com shows gmail. So I know that will work. They also say you can sync to the windows contacts. If that is correct or not I have no idea as I do not own an iPhone. I can not justify more than $500 for a device that simply takes phone calls.

I am aware of nothing that allows cync directly to the Thunderbird address book. Apple do not make one and as it is there device they create the software. There might be something in the apple store, but again I have no access to that. No device and no apple Id