So I know there are the default Attendee badges that give you standard access to the convention on the days it states. 

I know Trade Day badges give you access to trade day and its events.

Several game companies give out Gamemaster badges. Do these badges give any additional access to areas or access outside of standard attendee times? 

I know exhibitors/vendors have their Vendor badges that let them access the exhibit hall at times it is closed to attendees, in order to set up/tear down to be ready for sales each day and get out of there when the event is over. Do those badges give access to any other areas or anything? 

I thought I saw Press badges, right? Do they get special access to areas? Do they need to be accompanied or something or have a camera rolling while in those other non-attendee areas? 

I know VIG/Compnion badges give access to the VIG room and help get you to the front of the line for Room 500 events (any others?), and access to VIG events. Are there other “perks” or offers during the show weekend in terms of things like that, getting to skip lines or get into a special room or something? 

Are there other badge types? 

The VIG badge has their own lounge.   As for skipping lines, the main 'line skipping' is they get hotels 1st.   The early access to the vendor hall was stopped.

Seems like the overall question seems to revolve around 'are their other areas of the con that are super secret that you need X badge to get into?'.    I would say none that I know of.  At least anything of importance.   No hidden doors that you need to drop a coin in a slot to gain access ala John Wick.

ICC security badges unlock the ICC maintenance and admin area?

Yeah, the main gist of the question is which badges have access to which extra areas. Like vendors get access to the hall outside of normal hours, for logical important reasons. 

But is there anything different about a Gamemaster vs Attendee badge?

A game master badge *is* an attendee badge; it’s not different.   It just says “gamemaster” above your name.

As opposed to “exhibitor” or “all access” badges that are different colors to distinguish where they can go.

Yeah I mean kind of as KevinRG said, in the purest technical sense some badges can get you access to different areas in the fact that, like, my "Auxiliary Events" Auction volunteer badge gets me access to...the staging area behind the registration table and the auctioneering stage, haha.

Trade Day getting you access to things on Wednesday that nobody else can access (because, presumably, most other people would not be interested in them anyway) is probably the closest thing to what you are trying to figure out.

I suppose I do not know what press badges do, maybe they can go to some of the rooms otherwise off-limits to people not running the convention just to talk to them?

The main difference between Gamemaster and Attendee Badges, that I can tell, is that you do not get access to the housing portal with a GM badge. It considers housing is through the EO.
We were trying to get a hotel somewhere closer than way out by the airport, and once my GM badge came through, I no longer can shop the housing portal.

Thank you! That is an important fact to be aware of with accepting a GM badge!