I'll poke around a little more just to make sure, but then I'll update Wikipedia to match the NintendoAge list. Some quick searching, and I haven't found proof that any of these had a US release. The games listed on Wikipedia and not NintendoAge are: Wikipedia lists the Battlezone/Super Breakout 2-in-1 cart, but it doesn't show a separate cart for Super Breakout. Some quick searching shows that it definitely exists. The other non-Wikipedia game was Super Breakout. (Three actually, if you count Arcade Classics #2.) Neat! Sure enough, there are 2 Centipede games for OG Game Boy. Mistake? That's an odd mistake to make, so I clicked into each one: But it also lists Centipede twice, with a different Publisher and release year for each. Which are listed in a separate list on Wikipedia.
So there are some oddly complete titles, affecting the sorting, e.g., all the Disney games start with "Disney's" etc. This list is pulled from Wikipedia, so it's sorted alphabetically the way the titles are listed there. If anyone has any games to add to this list, I'd love to hear it.
There are 509 games on this list, including Rampart. Here's my current list if anyone is interested. I'd love to edit Wikipedia to have the best list, but I don't have any info on a NA release date. I've seen USA Rampart carts for sale on ebay, and I don't think they were fakes, but there has to be a more reliable source for this info. For example, it used to list Rampart as having a NA release, but then it later got changed to not having a NA release. Wikipedia seems to have the biggest list so far, but it's not based on anything official, and I'm a little skeptical. Anyone have access to a comprehensive list of every OG Game Boy game (grey cart) that was released in the US? I've seen lots of different lists and counts.