These are not nordgens, but mostly young players spawned from academy that cost no token to sign, and because they are 1* or 2* many players simply sell them at the first three days on the new season so that they could buy better players themselves. A player 3 levels above you selling a 2* will be a 5* for you.

A max academy spawn 2 players every 12 days and one of them could be signed for free, so you would see bunch of 18~20 year old coming up on first two days. Buy them while you can as they could remain 5~6* for seasons to come...