Players who played even a single game in the season counts and that includes injured ones.
This is the underrated stats that people mention. And what's good is most on the list I found are Celtics players.
George Mikan - Minneapolis Lakers (7 seasons: 1949-1954, 1956)
Jim Polard - Minneapolis Lakers (7 seasons: 1949-1955)
Frank Ramsey - Boston Celtics (9 seasons: 1955, 1957-1964)
Tommy Heinsohn - Boston Celtics (9 seasons: 1957-1965)
Bill Russell - Boston Celtics (13 seasons: 1957-1969)
Sam Jones - Boston Celtics (12 seasons: 1958-1969)
KC Jones - Boston Celtics (9 seasons: 1959-1967)
Wilt Chamberlain - Philadelphia/San Fransisco Warriors, Philadelphia 76ers, Los Angeles Lakers (13 seasons: 1960-1973)
Elgin Baylor - Minneapolis/Los Angeles Lakers (14 seasons: 1959-1972)
Jerry West - Los Angeles Lakers (14 seasons: 1961-1974)
Julius Erving - Philadelphia 76ers (11 seasons in NBA: 1977-1987)
Larry Bird - Boston Celtics (13 seasons: 1980-1992)
Magic Johnson - Los Angeles Lakers (13 seasons: 1980-1991, 1996)
Sidney Moncrief - Milwaukee Bucks, Atlanta Hawks (11 seasons: 1980-1989, 1991)
Kevin McHale - Boston Celtics (13 seasons: 1981-1993)
Clyde Drexler - Portland Trailblazers, Houston Rockets (15 seasons: 1984-1998)
Reggie Lewis - Boston Celtics (6 seasons: 1988-1993)
John Stockton - Utah Jazz (19 seasons: 1985-2003)
Karl Malone - Utah Jazz, Los Angeles Lakers (19 seasons: 1986-2004)
Mario Elie - Golden State Warriors, Portland TrailBlazers, Houston Rockets, San Antonio Spurs, Phoenix Suns (11 seasons: 1991-2001)
Robert Horry - Houston Rockets, Los Angeles Lakers, San Antonio Spurs (16 seasons: 1993-2008)
Tim Duncan - San Antonio Spurs (19 seasons: 1997-2016)
Glen Davis - Boston Celtics, Orlando Magic, Los Angeles Clippers (9 seasons: 2008-2015)
Among the active players, only these names have the record so far. Players under rookie contracts don't count:
Manu Ginobili - San Antonio Spurs (15 seasons: 2003-)
Tony Parker - San Antonio Spurs (16 seasons: 2002-)
Al Horford - Atlanta Hawks, Boston Celtics (10 seasons: 2008-)
Patty Mills - San Antonio Spurs (8 seasons: 2010-)
Jeff Teague - Atlanta Hawks, Indiana Pacers (8 seasons: 2010-)
James Harden - OKC Thunder, Houston Rockets (8 seasons: 2010-)
Kawhi Leonard - San Antonio Spurs (6 seasons: 2012-)
Draymond Green - Golden State Warriors (5 seasons: 2013-)
Role player or star, it is pretty impressive that Horford belong in such company.
EDIT: Added players noted by posters.