Speaking of Dassault, if we expand this to business jets, then any Falcon variant ending in DX certainly makes the list.

When bizjet OEMs try to build dumbed down versions of their aircraft to try to hit specific lower price points in the market, those aircraft generally sell poorly.

Gulfstream did this with the (old) G500 - a G550 with baffles in the fuel tanks and some software changes. I believe it cost Gulfstream more to build the cheaper G500 than the G550 due to having to install baffles in the tanks to artificially restrict fuel capacity.

So few of the things were sold that Gulfstream was able to reuse the G500 name on a new aircraft that has nothing in common with the old G500.