#2 Alexis Sánchez (Arsenal)
This would be a blockbuster move because it would weaken a rival while boosting City significantly. The only reason this could potentially happen is because Sánchez's contract runs out in the summer and this would be the only way for Arsenal to recoup some money from his transfer.
Arsenal is unlikely to sell to a rival especially seen as Sánchez is a key player. However, the Citizens are so far ahead in the league that they can't be classed as a direct rival this season.
Instead, the Gunners will be fighting with the rest of the top six for the Champions League spots. Losing the Chilean for nothing would be a much bigger loss than potentially losing points to City in the sole game they will play them as well as missing his presence in other games.
He clearly isn't happy being there due to them blocking a summer move and this will be impacting squad morale.
They could also potentially replace him with Thomas Lemar who has been linked to the club multiple times. They are different types of players but the French winger would definitely boost the squad.
Sánchez would offer City versatility because he could plan anywhere along the forward line or even as a playmaker. He has previous experience with Guardiola from their time together at Barcelona, so he already has an understanding of the Catalan's methods.
This would boost City's squad rotation as well as giving them more options off the bench to have an effect on big games.
His transfer would go against City's policy of bringing in youth in forward areas, but he is at his peak, and his experience would be vital in the tough games which are more likely to be in the Champions League rather than the Premier League.
It would also give Guardiola's team an additional threat because Sánchez offers central penetration from his ability to cut inside from the left side as well as another genuine goal threat.