Adobe Streamline & Dimensions
Both apps were rolled in to Adobe Illustrator years ago—but the features still don’t work nearly as well as they did back in the Mac OS 9 days when they were stand-alone apps.

Of course, if we’re talking about great apps that Adobe killed off:
Adobe Type Manager
GoLive
LiveMotion
PressReady
ImageReady

There is more, but those are some of the ones I used almost daily back in the day.