A short, sharp bit of rules trivia: Atraxa, Grand Unifier from Phyrexia: All Will Be One helpfully reminds you what the card types are, but the reminder text does not tell the whole story.
What Atraxa claims
When Atraxa enters the battlefield, you reveal the top ten cards of your library and may take one card of each card type. Her reminder text lists Artifact, Battle, Creature, Enchantment, Instant, Land, Planeswalker, and Sorcery.
The card type she leaves out
Do not believe her lies. There is another: Tribal. Tribal is a card type that lets noncreature cards carry a creature type, which is why Altar of the Goyf has the Lhurgoyf creature type. Because Tribal is a genuine card type, Atraxa lets you grab an Altar of the Goyf on top of an artifact like Bladehold War-Whip, squeezing an extra card out of the trigger. Fun fact: Altar of the Goyf is the only Tribal card on Magic: The Gathering Arena. Reminder text is not rules text, and this is a perfect example of why.