[Drake]

Quick glance at the list, a few terms I see missing:

ACM - All China Made. A blanket term for stuff originating from mainland PRC, often denotes lower quality/QC and/or knockoffs/counterfeit versions of brand name products (Magpull, etc). e.g.: an ACM Magpul stock.
BA - common abbreviation for Bolt Action
CanSoft - a type of airsoft gun with a clear or tinted plastic receiver, which is required for importation in Canada for guns that don't meet the minimum velocity requirements.
Clearsoft - all clear plastic guns, generally low end (like Canadian Tire/Walmart specials) and generally frowned upon for being junk.
Duster - another name for HFC134a (from duster gas, which is/was 134a). Nobody really uses this anymore except on certain specific guns which cant handle high pressure gas.
GBBR - Gas Blow Back Rifle (like GBB, but for Rifles)
Green Gas - pre-packaged (pre-lubed) and differently scented propane
King Arms - a Chinese (HK) manufacturer, usually good quality stuff
KJW - Juan Ju Works, another Taiwanese manufacturer, mostly gas guns as well.
MilSim - Military Simulation, a type of gameplay that places more emphasis on realism.
Propane - same stuff you use for camping, used to power GBBs/GBBRs; you need to get an adapter to fit on the Coleman or whatever tanks.
Real Cap - Magazines which hold the same amount of rounds as their real steel counterpart (usually 30 for rifles)
RWA - Red Wolf Airsoft, a well known HK retailer
Springer - a type of airsoft gun which is powered by spring cocking (you need to "crank" it before each shot, but it requires no gas or batteries to operate). Many bolt action and shotguns are spring powered like this.
VFC - formerly known as GB-Tech, a Taiwanese manufacturer. High quality parts.
WE - Wei-E Tech, a Taiwanese manufacturer of GBBs, GBBRs and AEGs (fairly popular GBBRs)
WGC - Wargame Club, a well known HK retailer


Probably a ton more stuff...