Major Factions:
Enclave - Enclave, Federal Government of the Enclave
NCR - NCR, Classic NCR, NCR Rangers
Ceasers Legion
Brotherhood of steel - East Coast, West Coast, Lyons pride, Classic, Outcast
Institute - Glows

Minor Factions:
Responders
Free states
Gunners
Reilys Rangers
Operators
Desciples
The Pack
Atom Cats
Great Khans
Yes Man
China

Locations:
The Divide
Diamond City
Arcadia
Big MT
Sierra Madre

Vault-Tec:
Vault-Tec
Vault 101
Vault 111
Vault 108
Vault 13
Vault 88
Vault 76
Vault 34/Boomers

Companies:
Red Rocket
Mass Fusion
Hubris Comics
Crimson Caravan
United States Space Agency

Girls Frontline:
16Lab
IOP Manufacturing
Griffin and Kryuger

Bioshock:
Columbia
Leutece LAbs

Command and conquer:
GDI
Brotherhood of Nod

Valve Universe:
Black Mesa

Firefly Universe:
Browncoats
Alliance

X-COM:
X-COM

Call Of Duty:
Group 935

Misc:
Gopher
Red Cross
Blue Tape Militia

May have forgotten some