Atletico de Kolkata/ATK (ISL)
Atletico de Kolkata have won the ISL twice and defeated Kerala Blasters both those times in the final.
Their last title came in 2016 when the final was played in Kochi.
With Helder Postiga as their marquee player, Atleico de Kolkata qualified to the ISL playoffs after finishing fourth in the league stage.
They ousted table-toppers Mumbai City 3-2 in the semifinal and beat Kerala Blasters 4-3 in penalties after the scores were 1-1 at the end of regulation time.
Atletico, unfortunately, were never the same.
Atletico de Kolkata became ATK (a few even called it Amar Tomar Kolkata) in the 2017-18 season.
Even though the partnership with Atletico Madrid had ended, the Kolkata team continued to use the same jersey colours and just took the abbrieviation of that as their official team name.
Following the end of the deal, a lot of turmoil was expected but ATK did not give any room for that and went ahead and signed a big name, Teddy Sheringham, as the coach. Ashley Westwood, former Bengaluru FC coach who had delivered two I-League titles, was roped in as the technical director. An over the hill striker, Robbie Keane, was the marquee player.
ATK's first win came after 5 matches, a narrow 1-0 triumph over Mumbai City. They followed it up with a similar result over Delhi Dynamos and NorthEast United but then endured a four-game winless run.
Sheringham resigned after a loss to Chennaiyin FC but Westwood couldn't change the team's fortunes as well. Westwood resigned after a 5-1 humiliation at the hands of FC Goa with the team being unable to win in 5 matches.
Keane helped them win their final game against NorthEast United and helped the team finish one spot from bottom with 16 points in 18 matches, five more than NorthEast United.