Some of these might already turn out good, but I've never seen any of them labelled "wonderkid'' in their profile. I don't expect them all to be wonderkids, but they should all have good potential.
Nick Powell, Mason Bennet, Keane twins, Adam Maher, Davide Petrucci, Gary Gardner, Jordan Rhodes, Cuenca, Fetfatzidis, Montoya, Gael Bigirimana, Islam Feruz, Andreas Pereira, Jetro Willems, Guidetti, Fischer, Romulo, Dennis Praet, Juan, Zakaria Bakkali, Lorenzo Insigne, Mats Daehli and finally, Davvy Klassen.
I'm sure I'll think of more.