Chelsea has always been a "rental team", and can definitely borrow more than 10 players per season, hence the name "taxi". However, Chelsea also borrowed troops from others, but most of the loans failed to succeed at Stamford Bridge.
Ricardo Quaresma was on par with Ronaldo in his debut, but after moving to Barcelona, the Portuguese star's development was gradually thrown off by the latter. Fortunately, he was able to regain his life at Porto and returned to the european mainstream in 2008 to join Inter Milan. But he didn't have a good time in inter's first season, being loaned to Scolari-led Chelsea in the winter window and reuniting with his former national team mentor. However, Scolari was fired by Chelsea in the middle of the season, and Quaresma only got five appearances at Chelsea, without any success.
In the summer of 2015, Chelsea let go of his old favourite Drogba and borrowed Falcao to take his third striker position. In fact, as early as the previous season, Falcao had experienced a huge failure at Manchester United, but his performance at Chelsea was only worse. Wearing the number 9 shirt, Falcao failed to fit into Chelsea's system, scoring just 12 appearances in the season, with one goal. Falcao was plagued by injuries during his season at Chelsea, and even though Diego Costa and Loic remy were injured in front of him, Falcao failed to step up at the right time.
Alexandre Pato and Falcao both joined Chelsea in the same season, but Alexander Pato moved in the winter window, half a season later than Falcao. In January 2016, Chelsea interim manager Hiddink said that the team did not have room for Alexander Pato, and how could the Brazilian still arrive on loan, it seems that this is the product of a communication error between the manager and the team's senior management. At Chelsea, Alexander Pato made his appearances in the picks after Diego Costa, Leuk Remy, Falcao and even youngster Bertrand Traore, with few impressive appearances other than scoring a penalty.
Mateo Kovacic, who was loaned to Chelsea by Real Madrid in the summer of 2018, was one of Sarri's key signings. However, during his loan spell, Mateo Kovacic's performance was mediocre, losing to junior Rubin Loftus-Cheek in the competition for position, and Barkley was only 550 points. Had it not been for the transfer ban on the team and the unexpected blows of Rubin Loftus-Cheek, Chelsea would not have bought out the Croatian. However, mateo Kovacic has made great strides after his official transfer, and to this day he is an indispensable member of the team's midfield.
Gonzalo higuaín was Sarri's old club at Napoli, when the club's centre-forward Morata failed to deliver a steady number of goals, causing Sarri to turn to the old club and borrow or sign Higuain outside the season for half a season. In that half year, Higuain's performance was not bad, at least more able to cooperate with Hazard than Morata, scoring five goals in 18 games in the season, and for a new brother who had just arrived in the Premier League, such a goal rate was already very good. However, Sarri, who signed him, left on his own in the summer when he saw Chelsea fall into a transfer ban, and Higuain, who belonged to his "concubine", was certainly not retained.