The Royal Flush Gang, who had not been seen since their second outing against the Justice League of America, back in 1967, don some new costumes in The Joker 5 (Jan/Feb 76) thanks to Marty Pasko, Irv Novick and Tex Blaisdell.
The story begins as the Joker and his gang murder a night watchman, so that the Joker can steal something from the man's possessions. The Joker's crew who appear in this story will continue to be his henchmen in later issues.
The main thrust of the Joker's crime spree in this issue is to steal four paintings by a dead artist, clues to the man's lost work, The Laughing Man. It turns out the Royal Flash Gang are after the same thing, and they wind up fighting over the paintings. Considering that it's five against one, for the most part, the Joker does really well, preventing the Gang from making off with the paintings. But then he gasses his own gang and adopts another identity, to evade the police.
When he goes to the prison to explain his actions to his men he reveals that he is really the grandson of the dead artist, and blames his facial colouring on the man's experimental paints.
As for the Royal Flush Gang, they have a new Ace this time, not Amos Fortune. He was the one who redesigned their costumes from clubs to spades, and provided their new high tech weaponry. This hasn't all gone over very well with the other members of the gang.
And despite all of Ace's tech, it's the Joker who beats them the second time as well. The four paintings are not merely clues to the Laughing Man, they actually are the lost painting. The Joker takes off with the dead painter's fortune, but the police are hot on his trail at the end of the story. Oh, and he admits to lying to his gang about his origin. The man he killed right at the top of the story was the real grandson, and he did that to steal the guy's diary, which allowed him to solve the clues.
Most of the Royal Flush Gang are next seen in Wonder Woman three years down the road, but Jack decides to launch a solo career, as Hi-Jack, and is next seen a couple of months down the road in Secret Society of Super-Villains.