I ran across this site about a month ago and it only just occurred to me now that I haven't done anything to share it on the site. So here it is!
If anyone wants or needs a bit of an introduction as to why you should visit, it's a repository of high quality scans of promotional flyers that game developers and publishers sent to arcade operators and owners. As a window into the past and another place to see art created for and around arcade games, it's absolutely amazing. The website, in addition to thousands of video game arcade flyers also has a whole half dedicated to pinball machine flyers. As someone who loves video games and its history deeper than most things, I got lost in this website and the only reason I'm not there right now is that I haven't had it in me to sink deep into the entire archive. Instead, here are some of my favorites to entice you:
A word of advice, if you want to see the arcade games hit the "video games" tab and then search by letter or whatever along the top. The "arcade game" tab is physical arcade cabinets/stations like the ones where you physically kick a ball or throw something. Also adding images to GB is busted so I'm not going to sit here for another 30 minutes to insert two more images. You should just dig around. One of my favorite things is seeing how different countries had different fliers, Dig Dug being a particularly fascinating example.