ROOKIE CARDS

I've never had any real interest in rookie cards, I collect cards as a hobby and have no interest in their value even though I can spend a lot of money on a card I need for my collection. I thought it might be an idea to start a post showing the rookie card for some of the best players in the world. Just one card and/or sticker per player, the one(s) considered to be the true ROOKIE card/sticker. I've started with Cristiano Ronaldo, Lionel Messi and Neymar Jr plus two youngsters who will probably be world-class stars in years to come and are already making names for themselves at their respective clubs. 
As I have said, I have no interest in rookie cards and my knowledge of them is very limited. For this project to succeed I need help from experienced collectors, please get in touch if you can help. If there is enough interest I will then include a link to this post (and any subsequent posts if this one gets too big) on the front page of my blog under the Index.
UPDATE (23-08-2019 13:21):  Henry Mehring has informed me I am wrong about the Jadon Sancho rookie card, an earlier card was issued in Japan, part of the WCCF 2017-2018 version 3 series. Vinicius Junior might have additional stickers in the Campeonato Carioca Sub20 2017 collection issued by Abril. Henry has also provided details for Christian Pulisic's rookie card which has been added below.

UPDATE (03-06-2022 08:45):  My feeble attempt to compile a rookie checklist has been blown out of the water by a thread on Blowout Cards Forums - Comprehensive Major Player Rookie List. The first post includes important information about codes, issue dates and naming conventions. The second post includes an often updated list of rookie cards. The list is updated and amended often and all this work has been co-ordinated by forum member fadster. I've taken a screen shot to give you some idea of what is included, but by the time you see this it's probably already out of date.