Whispers of the Muse (T1, Ext, S, Block) A favorite in "Turbo Xerox" (a blue deck which used minimal land but a ton of cantrips to thin out the deck), Counter-Phoenix (Shard Phoenix + Forbid) and Tradewind-Awakening (put Awakening on the stack, tap all your lands for mana, untap all your lands), Whispers has what might seem like a hefty price to pay for one card but you get to do it turn after turn after turn
Alternatively, you could cut white and go for something like Radagast, Wizard of Wilds or Tawnos the Toymaker
Nadu was a legendary design mistake, and one that very few players are sad to see gone
Others, like Inkmoth Nexus or High Market, only produce colorless mana
Plains #B1 (Ravnica Weekend) by Alayna Danner Magics latest visit to Ravnica introduced elaborately themed Guild lands as promotional cards for Ravnica Weekend, and Danners Azorius Plains-Island Diptych is a simply stunning addition to the series