Granted, both were really young, but the awful 1976 Montreal Expos (55-107, .340) had Gary Carter and Andre Dawson. The next year they finished 75-87 while adding Tony Perez.
If you look at hockey in the “original Six” era of 1945 to 1967 you can find a lot of lousy teams with
a number of Hall of Famers. The 1946-47 Chicago Blackhawks finished 19-37-4 (42 points) and had Hall of Famers Max and Doug Bentley, Bill Gadsby, Bill Mosienko and Clint Smith. The back up goaltender Emile Francis made the Hall as a coach/GM (he also invented the practice of a goaltender having a stick in one hand and a baseball glove on the other.).
The 1980-81 Edmonton Oilers finished tied for 13th in the standings and had a LOT of great young Hall of Famers. 20 year olds Wayne Gretzky, Mark Messier, Jari Kurri, Glenn Anderson and 19 year old Paul Coffey.
Baseball has a disproportionate amount of Hall of famers in the 1920s/30s era because the Veteran’s Committee ofthe 1970s and 1980s went hog wild putting these guys in. Frankie frisch gets a lot of blame for this, which maybe unfair since he died in 1973, driving back from one Veteran’s Commitee meeting. The 1926 New York were mediocre, going 74-77 (manager John McGraw probably thought that was terrible. But there was a lot of Hall of Famers in their prime: 1B George “Highpockets” Kelly was 30, 2B Frisch was 27, OF Ross Youngs was 29, SS Travis Jackson was 22, 3b Fred Lindstrom was 20 but played regularly and hit .302 Bill Terry was a part time player at age 27. Mel Ott was only 17 but hit .383 in 60 at bats. No Hall of Fame pitchers, although Fat Freddie Fitzsimmons was pretty good and was only 24. Billy Southworth was an aging reserve outfielder and made the Hall of Fame as a manager (his philosophy was don’t be like John McGraw).
The 2007-08 Miami Heat finished 15-67, and they had Dwayne Wade, Alonzo Mourning, and for half of the season Shaquille O’Neal. (Granted, Wade and O’Neal were injured for part of the year.)
The 1996-97 San Antonio Spurs finished 20-62, got the first pick in the draft, selected Tim Duncan and within two years had won their first of four NBA Championships. That 20-win team technically had both David Robinson and Dominique Wilkins, although Robinson was injured and Wilkins was in the extreme twilight of his career.
It’s harder finding examples in basketball. If you have three or four Hall of Famers, particularly in their prime, you’d better have a damn good team, 'cuz basketball only has five guys on the floor at once.