The Queen's Gambit is OriCon's most elite squadron of rigger pilots (at least during the Golden War), led by Tea Kenridge. Jace Rethal is a member, and Orth Godlove used to be before being suddenly promoted and assigned to the Kingdom Come. The squadron is a part of the Kingdom (COUNTER/Weight) sent to stop an Apostolosian superweapon.
For a while Ibex sways members of the Gambit into following him and calling themselves the King's Gambit, to Tea's fury. She eventually wrests back control of the group. After the Kingdom is disbanded and the war ends, the Queen's Gambit is also disbanded. Many former members of the Queen's Gambit join the Weightless, which goes on to clash with the Chime years later.
The Queen's Gambit is officially reconstituted under Tea's leadership in the midst of the Golden War anniversary celebrations, though the existence of the Weightless is swept under the rug ("An Astonishingly Illegal Ship").