In addition to PSOne games and made-for-PSN games, the Japanese PlayStation Store features a modest selection of games from NEC/Hudson's PC Engine system, in its "PC Engine Archives." In a massive update, Sony is adding 1/7 of the games from another NEC console, the SuperGrafx. Okay, so it's just one game.
Next week, Hudson's After Burner-style shooter Battle Ace will be available on the PlayStation Store next week, along with Victory Run, a racing game for the original PC Engine. Strangely enough, the Wii Virtual Console is also host to a single SuperGrafx title in Japan, but it's a different one: Capcom's Ghouls & Ghosts. Of course, both the Virtual Console and the PlayStation Store are devoid of SuperGrafx games outside of Japan.