Be careful here, because even those that seem to speak for themselves require (cultural) context to appreciate fully. Take Rembrandt's portrait of St. Bartholomew. It's unquestionably a skilled production, and aesthetically pleasing. But it's also, on its face, just an old guy holding a knife.

If you learn the guy's name from the plaque next to the frame, and you know the word "saint" and are familiar with the reasons that title is applied, that probably gives you some impression that the knife is not going to be used to eat supper. (It's interesting to imagine viewing the and not knowing these things, in my opinion.) But only if you actually know St. Bart's (horrific) story do you understand the look on his face and really grasp the depth of Rembrandt's depiction.

This same problem applies to modern->contemporary art. In some cases the cultural context is, ironically, "people thought art should be produced for its own sake", which is harder to engage with if you happen to also not like the surface aesthetic. But it doesn't stop the artifacts from being art.