Notable players using family members
Lionel Messi, Sergio Ramos, David Alaba, Fernandinho, Arjen Robben, Claudio Marchisio, Ilkay Gundogan, Neymar (dad), Juan Mata (dad), Francesco Totti (qualified), Eden Hazard (no agent)
I found this list. Few good players in there. But lets remember the argument isn't that you can't be a top player without an agent, its that you leave yourself at a disadvantage early in your career when it comes to contract discussions if you have someone who isn't 100% clued up on business deals negotiating your deals.