They allow you to draw more cards, heal your Pokmon, or manipulate the game state in your favor
All the one drop elves become more valuable and all the Rampant Growth things become less valuable
1 Traditional foil rare or mythic rare that's an extended-art, borderless, or retro frame card, or one of the following: A double rainbow serialized Eldrazi (250 of each) A foil-etched rare (9.3%) or mythic rare (3.9%) A traditional foil Special Guests mythic rare (10 cards total4.4%) A textured foil Special Guests Elemental (1.9%) or DFC planeswalker (1.9%) The remainder of this slot has the same content as the non-foil slot above with the percentages reduced appropriately to account for the inclusion of serialized, foil-etched, textured foil, and Special Guests cards
It often costs far less than 6 mana despite being an incredibly powerful threat, and its a devil to interact with between the immense ward cost that makes it hard to target and the triggered ability that makes it impossible to block
Of course, you could just cheese the last ability
Imperial Recruiter To prove just how dire the selection is for red, Imperial Recruiter makes the colors list of best MTG tutor cards