I don't think De Gea will be devoid of enthusiasts after his contract with Manchester ends. I think Al Nassr is one of the leading teams to get De Gea because he would be a great signing if Al Nassr can convince De Gea to accept their offer. I think De Gea will take advantage of this free time to go on vacation before he decides to accept the offers that come his way. Other than that I think the level of ability he has will make him the target of many European teams or outside Europe.
So far, it has been reported that Manchester United will make another approach to convince De Gea to return to the team. However, seeing the treatment that Manchester United management did to De Gea, I think their efforts to convince De Gea will be difficult to achieve.
I don't know much about De Gea's situation at Manchester United, but maybe the negotiation process will still be considered if it turns out that Manchester United can't sign a better goalkeeper. Right now De Gea is available as a free transfer player, so he can go anywhere as long as he feels it is more profitable there.
Al Nassr are interested in signing De Gea, but I think Al Nassr's interest in De Gea has gone down. After all, De Gea is still very likely to play in Europe instead of the Arab Pro League, but all his decisions really depend on what his future plans are.