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 real strength of this commander is likely as a partner for color access and slowly gaining little bits of valueor doubling up on G/U commanders to go all-in on value

This means you can tutor out something like Consecrated Sphinx on your first main phase and then have it ready for your upcoming ninjutsu trigger

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

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