So, here's my challenge : why not make that abilities-soup land actually fair and therefore enjoyable in gameplay, by adding some costs? Sounds fun, but how to fit all the sixteen abilities in only one card text? Yeah, that was a challenge, and here's the solution I came up for:
Library of Council
Land T: Add one mana of any color. 1,T: Target creature gains haste until the end of turn. 2,T: Draw a card. 3,T: - deals 1 damage to any target. 4,T: Tap or untap target permanent. 5,T: Add WUBRG. 6,T: Roll a six-sided die. Resolve a casual effect according to the result.
So, yeah the design of this card is pretty crazy, because I'm using here the same trick of Urza, Academy Headmaster to make fit an otherwise unfittable amount of abilities at random. So, you will need a dice and a piece of paper to write those extra six effects which are the six most powerful abilities of the original library:
at 1: You may pay 0 rather than pay the mana cost for spells that you cast this turn.
at 2: Choose up to nine cards you own from outside the game and put them into your hand.
at 3: Search your library and/or graveyard for a card and put that card into your hand. If you search your library this way, shuffle it.
at 4: You gain 50 life.
at 5: Destroy or return target permanent to its owner's hand.
at 6: You may search your library to up to nine land cards and put them into the battlefield. Shuffle your library afterwards.
Yeah I know, they are not exactly the same, some are tweaked or fused together to fit six slots and make worth paying the cost.
And I recognize that some of the effects are totally crazy even at six mana, but the fact you can't control them and that you can end to have an effect you don't wish to have while you are losing might be balanced enough to be worth the gamble without necessarily being game-ending. Playing this ability should be for both players an exciting risk to see how it turns out rather than a predictable and oppressive effect.
Obviously this card would never see the light of day in black border for tournaments play (too powerful / too complex / too chaotic / require dices / rules issues etc) and would obviously still be the best land of the game, but I can see this being printed as a silver border joke card. Surely, I would play with and against this inside a pretty casual and relaxed environment, ideally a multiplayer EDH game and see what happens.
Anyway, this is my take on the library to create a land that somehow have the "feel" of the original Library of Congress without being completely nonsense, surely not a perfect result but at least a first try.