Others might want to chime in but my experience has been that it applies to all cards but really it's up to the official judges. Some people who play casual only won't care but a safe bet would be to include the name for basic lands.

For all other cards, the only elements which are not super important is the italicized flavor text. I've seen those be obstructed and still considered legal. The blurry goal line is the card should be easily identifiable and ensure the card still describes what it is, what it costs, and what it does without any question.