In some cases involving linked abilities, an ability requires information about the exiled card. When this happens, the ability gets multiple answers
New cards are usually driven by a mix of play demand and collector appeal
They have anywhere between 8 to 11 packs and also include sleeves for the cards, a checklist book to help you track the cards to collect in the set, dividers, dice, and counters for playing the game
Harrow, for example, would allow you to search your library for two basic lands and put them into play
Needing to play against blue or black opponents is a bit restrictive, but this card punches well above its weight as a cheap, interactive 2-for-1
Zur is even listed on EDHREC as being a common curse commander, which I find hilarious