People trying to sell their game.

LTG : )

Top rated games are considered A list. Everyone has an opinion about which ones. The consensus lists, Pinside and IPDB at least have statistically significant amounts of responses. I'd start there.

If it's on a list, then it's a-list.
duh.
-mof

What I like and play often . What others pinheads care for not a big influence to me. Also A list changes with time and software revisions if you are into new titles . Enjoy the day Shane

This is probably not helpful, but an A-list game is simply a game on the A-list!

You need to ask for the definition of A-list!

All kidding aside, there is no solid definition or actual list, it's subjective, but in general it means universally acclaimed, highly desirable, and expensive.

Usually only more modern pin collectors (SS/DMD) are concerned about a game being A-List or B-List or C-List.

A-list games are ones I own.
B-list games are ones I want.
C-list games are ones I don't want.

Any game not Stranger Things, Black knight SOR or Munsters

WoodRails
A-List : Mermaid, Gusher, Dragonette, SeaWolf, Daisy May, Rocket
B&C-List : Most 2&4Player pins from the 50s
1960s
A-List : Most of the AAB pins, Star-Jet, Slick Chick, WMS Jungle, Pins with BG animation
B&CList : Most Multiplayers, Most CCoin pins
1970s
A-List: Atlantis, AbraCaDabra, Quick Draw FireBall, 4Mil BC, CaptFan, Late 70s GTB single players, Grand Prix, Space Mission
B&C List : Most CCoin pins, lots of early to mid 70s pins from BLY/GTB/WMS

Tastes change all the time with EMs as to what is considered desirable or collectible.

Actually . . .

A-list are games I own, especially the ones I want to sell (I will demand the highest possible price regardless of condition with zero room to negotiate)
C-list are games someone else owns and I want to buy (I will offer a lowest possible price, point out every minor flaw, and beat you down until you succumb to my offer)
B-list games are everything else

Lotr

highly sought after pins that don't last more than a few days on the marketplace.

A List: Atari Space Riders, Atari Airborne Avenger, Allied Leisure Getaway (Disputed A list: (Capcom) Airborne, (Stern) Avengers, (Stern) Avatar, (Williams) Algar)

B List: Bally BMX, Bally Hardbody, Bally Grand Slam (Disputed B list: (Stern) Batman: Dark Knight, (Gottlieb) Baseball. Very borderline, cause of much consternation: (Midway) Black Rose -- some people try to get it on the B list by calling it Bally Black Rose, but it's under the midway imprint, so it's disputed at best)

C List: Capcom Pinball Magic, Capcom Airborne

and the lists go all the way to Z

Z list: Zaccaria Clown, Zaccaria Devil Riders