Nights of Cabiria and Taxi Driver both have plots. Not traditional plots, but they do have plots.
Taxi Driver is technically guided by the character arc of Travis Bickle, not by an ABC guideline. So, though, it follows that arc for what seems like a conventional route of a plot, it seems to flow from Travis's consciousness. Besides, Scorsese's first film to have a plot was actually Cape Fear followed by The Departed.
Most films by Anger or Stan Brakhage definitely do not have plots or any sort of conventional narrative in the least. That is what I prefer overall, or a character-driven arc told as subjectively as possible.