Multiplayer first person shooter games with 8-player online support

Duke Nukem 3D Megaton Edition

Players: 8 local, 0 online

Duke Nukem 3D: 20th Anniversary Edition World Tour

Players: 8 local, 0 online

Serious Sam: The First Encounter

Players: 16 local, 0 online

Insurgency: Sandstorm

Players: 8 local, 0 online

Unfortunate Spacemen

Players: 10 local, 0 online

Quake

Players: 16 local, 0 online

Serious Sam: The Second Encounter

Players: 16 local, 0 online

Contagion

Players: 8 local, 0 online

Duke Nukem 3D

Players: 8 local, 360 online

Synergy (HL2 mod)

Players: 16 local, 0 online

Starship Troopers

Players: 8 local, 0 online

DOOM 3: Last Man Standing (Mod)

Players: 16 local, 0 online

Mission Against Terror

Players: 8 local, 0 online

Duke Nukem 3D: 20th Anniversary Edition World Tour

Players: 8 local, 0 online

AirBuccaneers

Players: 16 local, 0 online

Hexen 2

Players: 8 local, 0 online

Brink

Players: 8 local, 360 online

Resistance 2

Players: 8 local, 0 online

Combat Arms

Players: 8 local, 0 online

Serious Sam HD: The First Encounter

Players: 16 local, 0 online

Star Trek Elite Force 2 (HZM Co-op Script Mod)

Players: 12 local, 0 online

Coop Warfare (F.E.A.R. MOD)

Players: 16 local, 0 online

Serious Sam HD: The Second Encounter

Players: 16 local, 0 online

Marathon: Durandal

Players: 8 local, 360 online

Brink

Players: 8 local, 0 online