Valtteri Bottas
It is widely understood that Bottas came quite close to signing for Ferrari last year and this year too it seems that he will be strongly linked with the team. During his tenure with Williams, the Finn has impressed one and all with several strong performances which include a total of nine podiums.
During his tenure with the team, he has proved to be very consistent and has secured strong results even under pressure from several drivers behind. Furthermore, he has been much more consistent than Perez and more experienced as compared to Sainz, the two other most probable candidates for the seat with Ferrari next season.
In the past three years, he has held his own very well against an experienced Felipe Massa, who had proved more than a match to Raikkonen during his time with Ferrari. Thus, if the Finn does join Ferrari, he will provide much needed overall stability to the team, an aspect in which the team has struggled recently mostly due to the inconsistent form of Raikkonen.
All these factors are enough to make him one of the strongest contenders towards joining the prancing horse next season.