Said fat kid with his trusty hawk, prior to being deep-fried and eaten.
However, sometimes they decide to reference their games within their other games and even connect their plot lines and characters together and hint that their games (or at least the ones they openly admit to) all take place in the same universe as one another. This ends up becoming an easter egg hunt for V.Fame fans as they try to piece together the timeline that these games take place. We'll give you a head start by pointing out some cameos that are (most likey) references rather than laziness.
Digimon 3 Crystal (Digital Monster 3)
Alright, this one isn't the most solid evidence of a "cameo" but since the character got more attention than the other NPCs I figured I'd throw him in. So this guy is your generic go-to adventurer meant to fill in the role that the lead Pokemon trainers do (and bares a resemblance to Ethan from Pokemon Gold.) It's hard to say what game came first, but I'm guessing the order's something like Digimon 3>Digimon Pocket>Pokemon Ruby. Anyway, in Digimon 3 he's called "Small Breeze" and is just some kid who took a nap in a sewer system early in the game. You meet up with him at the first town's bar afterwards to get info on where to go next aaaand...That's it.
In Digimon Pocket, he's cast as the main protagonist who's supposed to be the player (as the ending and text refers to the player in first-person.) He doesn't actually have a name here, and he's wearing blue for whatever reason (a later revision replaces him with Tai, who better fits the palette but whatever.) And in Pokemon Ruby (or Chong Wu Xiao Something Something) he's the final boss(!) Where he's called Shutulin in the Engrish version. He dons his traditional red garb here and just acts like a gym leader. After that, he was never seen again in any future V.Fame game to my knowledge. Maybe it's because he's by a different artist, as the art style in Digimon 3/Pocket is a bit different from the later V.Fame titles drawn up by Zhu Zhenxin. But I can't tell, because those two games don't have credits.
V.Fame Television and its Newscasters
Crazy Monopoly is ripe with self-references, as we'll see more of later on. The two are from Vast Fame's own television station (yes, really. And they're the ones hosting the Monopoly show as well) that keep viewers up to date on the progress of the players. They pop up and crack jokes whenever an event happens in-game and to summarize everyone's progress after a year. They made a guest appearance in Shi Kong Xing Shou late in the game reporting that a meteor's headed to earth and that everybody's doomed. They just use generic NPC portraits for the two, as they didn't get any in Crazy Monopoly. In case you're wondering, the sequel (Crazy Richman 2) has a different newsroom and a new host (who might just be the guy on the left; they look very similar...)
Super Fighter S and Zook Hero Z
...And we see Crazy Monopoly again, with an in-game event that's mentioned in the manual but I have yet to actually encounter. Here V.Fame shamelessly references two of their old titles (pictured) at a "VF Seminar". For the curious, Rock Hero Z (supposed to be Zook Hero Z, but the Chinese characters for "Zook" and "Rock" get mixed up a lot) is the prequel to Zook Hero 2, or Rockman DX3 as it's better known as. Amusingly, they got the title (and a lot of the text, surprisingly) accurate in the actual English release of the game, but screwed up later on when they made Crazy Monopoly.
And Super Fighter S/Super Fighter 99 is a fighting game that they worked on that I believe is a color/minor hack of an existing Takara game. I think. I don't fully remember, but it came out in 1999, which is the year V.Fame started making games of their own.
Xin Feng Shen Bang
Shui Hu Shen Shou
Xin Feng Shen Bang
And lastly we have the Jade Unicorn. He first appeared in the 2001 Pokemon clone Shui Hu Shen Shou (or Shawu Story to some) as the protagonist (Yan Long's) starter monster. Despite looking like a dragon (and having two horns) he really is called the Jade Unicorn. He made a guest appearance in the 2002 RPG Xin Feng Shen Bang as a cameo boss fight. Supposedly Xin Feng Shen Bang came first, as in Shui Hu Shen Shou it mentions the monster being captured in a far away land. It's also worth noting that the Jade Unicorn's dungeon in XFSB has graphics lifted from the fire dungeons in SHSS.
And that's all the cameos I've come across. I have yet to play or beat all of the V.Fame games, so I might be missing some things. Still, it's neat to see how all their games relate to one another in a way that isn't reused programming or graphics.