I found out Yume Nikki wasn’t the only game to get a bunch of fan games inspired by it.
There’s a game called OFF which has a bunch of [spinOFFs] (http://off.wikia.com/wiki/SpinOFFs_(OFF_Fangames)) by various people. Not near as many as Yume Nikki but I think there’s at least 20 completed games so still that’s pretty impressive. I just hope all the downloads work. I don’t know how up to date that page is kept.