Quake 2 shipped in December 1997 and kept selling long enough that it grew a proper family of expansions: two official mission packs, a community compilation, a modern episode released 25 years later, and a couple of unlicensed retail boxes that most players never knew existed. This is the full list.
Developed by Xatrix Entertainment and published by Activision. You play Joker, a Marine who landed on Stroggos at roughly the same time as Bitterman, the campaign hero of the base game. New levels, weapons and enemies.
Developed by Rogue Entertainment, also published by Activision. Its Marine is Stepchild, another survivor of the same botched landing. Remembered mostly for its turrets and for being noticeably harder than the base campaign.
Not a campaign but a compilation: id Software collected some of the best custom maps, models and mods the online community had produced in the game's first year and Activision put it in a box. A time capsule of the early mod scene.
Made by MachineGames, the studio behind the modern Wolfenstein games, and released as part of the Quake II remaster. Six Marines land at different points on Stroggos to recover a data disc. If you buy the remaster today, this is included, along with both 1998 mission packs and the campaign from the Nintendo 64 version.
Two retail expansions shipped on CD-ROM without id's blessing, a thing that could still happen in 1998.
Developed by Canopy Games, published by Head Games. Poorly received then and now, but a genuine curiosity for collectors.
Developed by Team Evolve, published by Macmillan Digital Publishing. The better regarded of the two, and its levels still circulate as a free download.
A third unlicensed pack, Unseen, was finished but never sold and eventually surfaced as a free mod. A fourth, Vengeance, never appeared in any form.
The remaster is the simple answer for the official content: everything except Extremities is in the box. For the unlicensed packs and the classic experience, a source port is the way in; see Playing Quake 2 in 2026.