For a small cost, it makes your opponent mill seven cards, packing quite the punch
Vampiric Tutor I am not a huge fan of Vampiric Tutor but only because I don't like having to play it
Here are the prices of the top 20 most valuable Revised cards as of January 2021 versus the prices when my book was published (August of 2018)
For the low cost of nothing (at least in terms of card economy), you get a creature that blocks almost all early-game creatures
Dark Ritual allows you to take advantage of drawing multiple cards a turn back during the black summer of Magic , it wasn't unusual to see a player drawing 4-5 cards a turn every turn of the game using Necropotence to fuel their crazed game of "holy cow, is this for real?" No other card in Magic has allowed a player to draw so many cards turn after turn so cheaply
Essentially, if it made you choose one or more options, regardless of card type, it made the cut so I could showcase the best flexible spells Magic has for you