Here's a series of things RPG Maker games have gone on to turn into. A few that I know of, at least. Keep in mind, I'm talking official stuff, not really cool fan film remakes, fan art, countless fan games, and the like some of these games receive. Notable, a lot of them were RPG Maker horror games:
-Corpse Party has gone on since it's original 1996 game to go on to get a remake on PC (in Japan) and PSP, which has spun-out a number of sequels, an official manga adaption, a prequel single-episode anime OVA, and a four-episode anime OVA adaption.
Corpse Party's manga and OVA anime.
Palette (a 1997 Japanese RPG Maker game) won a game development contest, and used the funds it won to make a PSX remake.
PSX cover for the remake, "Palette: Forget Me Not".
Yume Nikki has gone on to get a lot of official merchandising, and recently got an official manga and novel adaption.
Some Yume Nikki phone merchandise and the manga cover.
Witch's House got an official prequel novel.
Official prequel novel cover.
Ao Oni got a manga and is now getting a film.
Ao Oni manga cover and film teaser.
There's other stuff, but these are things I know off the top. Interestingly, a lot of what I posted only happened in the last year. RPG Maker games have gotten a lot more popular in the East (and West as well) in the last two years.