Thespians Stage Clearly valuable in Lotus Field and Amulet of Vigor decks, Thespian's Stage has even more value in EDH, where you know someone has a busted land like Cabal Coffers or even The World Tree, and the fact that you can shift it as needed is just awesome

higher rarities will start to mix and match effects): Artifact destruction Artifact or enchantment destruction (Naturalize) "Bounce" (Returning nonland permanents to owner's hand) Card drawing Card filtering Creature destruction Creature lockdown (Pacifism and Dehydration) Creature regrowing (Raise Dead) Creature unblockability Counterspell Damage prevention (Fog) Direct damage Discard Draining creatures and/or players Enchantment destruction Fighting "Flickering" (exile and return a creature to the battlefield) Flier destruction Forced blocking Forced sacrifice "Impulsive draw" (exile a card or cards, can cast until end of turn) Land fetching Life gain Looting/rummaging (drawing and discarding, and vice versa) "Milling" (putting cards from top of library into graveyard) "Panic" (some number of creatures can't block) Power/toughness pumping (Giant Growth) Tapping creatures (including "freezing" them, where they don't untap) Temporary stealing (Threaten) Token making Uncommon Complexity Uncommon gets to raise the bar a little on comprehension complexity and a bit more on board complexity

There's a wide selection of these to collect, but this one was special as it promoted the GAME BOY game
Bulk lots, pre-loved collections, and even unexpected gems often appear in online auctions, giving you a chance to score rare cards while supporting a good cause
Four mana is a ton for a counterspell, so it had better do something else to justify its cost
Glimmering rainbow