#3 Roberto Firmino
Ralf Rangnick and Roberto Firmino enjoyed the briefest of partnerships at 1899 Hoffenheim. Although the German manager was responsible for bringing the Brazilian forward to the club in 2011, Rangnick resigned just a day after signing Firmino.
Before the manager quit the club in protest over the sale of Luiz Gustavo to Bayern Munich, Rangnick pulled off an astounding transfer. Firmino was mired in obscurity at the time, plying his trade for Figueirense in Brazil's Serie B.
Rangnick gambled on the 19-year-old forward, who had just one full season of experience. It paid off, as Firmino made 153 appearances for the German side, scoring 49 goals. In 2015, Liverpool made him the second-most expensive signing in their history by paying €41 million for the striker's services.
He has become an integral part of one of the most feared attacking trios in world football, scoring 70 goals in 219 Premier League appearances for the Merseyside club. Firmino has also won the Premier League and the Champions League with Jurgen Klopp's side.
#2 Sadio Mane
Arguably Rangnick's greatest signing, Sadio Mane is a bonafide superstar. The Senegalese winger finished fourth in the 2019 Ballon d'Or race, and is widely regarded as one of the best players in the world.
Rangnick, who was Red Bull Salzburg's director of football in 2012, signed the then-20-year-old Mane from Metz for €4 million. With just over a season of experience in France's second division, it was an ambitious transfer.
However, it proved to be an inspired decision, as Mane went on to make 87 appearances for Salzburg, scoring 45 goals and assisting 32 times.
Unfortunately, Rangnick and Mane's time together ended on a sour note, as the winger refused to play for the Austrian team and demanded a transfer. He was eventually sold to Southampton in 2014 before he joined Liverpool for €35 million in 2016.
#1 Erling Braut Haaland
Erling Haaland is the most in-demand player in world football right now. His first step before bursting onto the world stage came under Ralf Rangnick at RB Salzburg. The Norwegian rose through the ranks at Molde, where he scored 20 goals in 50 appearances as a teenage prodigy.
Haaland took a step up to Europe's big leagues by joining Salzburg and Rangnick in the Austrian Bundesliga. The 18-year-old left Ole Gunnar Solskjaer's Molde in an €8 million move in early 2019. Despite being targeted by clubs like Leeds United during his time in Norway, Haaland truly caught the eye of Europe's biggest clubs while with Salzburg.
Although his time with Rangnick's team was brief, Haaland displayed remarkable development. He registered seven assists and 29 goals, of which eight came in the UEFA Champions League, where he scored a hat-trick on debut, two years ago.
Less than a year later, Erling Haaland was snapped up by Bundesliga giants Borussia Dortmund for €20 million. The star striker has bagged 72 goals and 19 assists in 71 appearances for Marco Rose's side. Haaland is expected to fetch a fee north of €100 million when he eventually moves to one of the continent's elite clubs.