four or more card types mtg Let's Play a Game - Duskmourn: House of Horror #105 (English) then that player shuffles his or her library. What exactly does it mean

That means you are not splashing that effect unless it is good enough for a real commitment to the color or lack thereof, just like how splashing Treetop Village is often not the best idea (but not always!)

The aforementioned Mike Flores piece was here on our own website thirteen years ago

Aristocrats decks aim to gain value through repeatedly sacrificing one's own creatures, often including powerful sacrifice outlets, creatures with death triggers, recursion, and effects that make the act of sacrificing creatures more beneficial

Could any of those 1993 players have guessed the future value of these cardboard rectangles

The official rules are as follows: (a) You may choose to pay [cost] rather than pay this spell's mana cost