2. Dr. No 
Dr. Julius No was Bond's first nemesis in the franchise, and bringing him back would truly bring the series full circle. Dr. No is a member of SPECTRE, and as I was talking about with Blofeld, if Quantum came back, Dr. No could be part of the organization. The idea of villain with metal hands would be a great visual, especially since the character wears black gloves in Dr. No. In Dr. No, the character was very stoic and calculated- an interesting way to re-imagine the character would be if the the "Doctor" angle was played up, with him conducting horrifying experiments- a sort of mad scientist.