As we noted a few days or so ago, Del Rio is looking to leave the WWE all together. His contract will expire in due time, and so tons of other promotions have shown a keen interest in signing Del Rio to their show. 

Despite him leaving AAA, they seem like they maybe interested in signing him on back. He had kept the secret he signed with the WWE  from them and never lost the title. He was a big draw for that promotion, and they seem desperate enough to bring him on board once again. 

Lucha Underground, another promotion, has shown interest in him as there are supposedly talks going on between them and people who know Del Rio possibly bringing him back for the next season of tapings. Lucha Underground, however, needs to have a lot more income if they wish to convince to sign him. 

TNA is another one throwing the ball around with possibly signing Del Rio, and keep the promise that he'd be a top guy for the company. They did want him last year, but plans just fell out as Del Rio decided to return to the WWE. 

NJPW, and the promotion called Glory Kickboxing shows interest as well. NJPW is no stranger to signing former WWE or even TNA superstars to the roster.  However, it seems unlikely Del Rio would want to sign for either because he's not interested in Japan style, or even some kind of form of combat fighting like kickboxing.