- GW - Games Workshop
- WH40K, W40K or 40K - Warhammer 40,000
- WHFB - Warhammer Fantasy Battle
- BFG - Battle Fleet Gothic
- LotR - Lord of the Rings
- TT - Table Top
- BB - Bulletin Board (unlikely) or Blood Bowl
- WHQ - Warhammer Quest (dungeon exploration)
- DoW - Dawn of War (the GW Computer game)
- WA - Winter Assault (the DoW expansion pack)
- DC - Dark Crusade (the DoW expansion pack)
- WD - White Dwarf magazine
- SM - Space Marine
- CSM - Chaos Space Marine
- DE - Dark Eldar (possibly Dark Elf as well, but not that I've seen)
- BA - Blood Angels (the SM Chapter)
- DA - Dark Angels (again, the SM Chapter)
- SW - Space Wolves (again the SM Chapter) or Star Wars
- WFRP - Warhammer Fantasy Roleplay
- IG - Imperial Guard
- Ult - Ultramarines
- WH - Witch hunters
- DH - Daemon Hunters
- BT - Black Templars
- FC - Force Commander
- HB - Heavy Bolter
- GK - Grey Knights
Any other suggestions on useful abbreviations to list, just tell me