I might have some neogeo flyers I can sell you, but as is almost always the case with this subject, confusion fills the air. Posters, flyers, ads, art work, art packs, etc. Everyone calls these things by different names. So it's hard to know exactly what your looking for. Here's how I call it:
Posters: these are huge, big size, hang on a wall art works.
Flyers: these are legal paper sized advertisements that SNK gave out at trade shows & to arcade distributors for the operators to see what was available & coming soon.
Art packs: these are the smaller half paper size sheets included inside the MVS kits.
I have a bunch of the last 2 items available for trade & sale.