The first is that it doesnt actually give you a chance to tap down the creature, meaning you have to either wait for its controller to tap it or use it while the target is already tapped
If you are new to the game, start with a set that has cards you enjoy, accessible prices, and a good mix of popular characters

Release date: 2018-02-05 Act of Heroism Akroma, Angel of Wrath Akroma's Vengeance Angelic Page Armageddon Auramancer Cloudshift Congregate Darien, King of Kjeldor Dauntless Cathar Decree of Justice Disenchant Fencing Ace Fiend Hunter Geist of the Moors Gods Willing Griffin Protector Karona's Zealot Knight of the Skyward Eye Kongming, "Sleeping Dragon" Kor Firewalker Loyal Sentry Luminarch Ascension Lunarch Mantle Noble Templar Nyx-Fleece Ram Ordeal of Heliod Pacifism Path of Peace Promise of Bunrei Renewed Faith Rest in Peace Savannah Lions Squadron Hawk Swords to Plowshares Thalia, Guardian of Thraben Urbis Protector Valor in Akros Whitemane Lion Accumulated Knowledge Arcane Denial Bident of Thassa Blue Elemental Blast Blue Sun's Zenith Borrowing 100,000 Arrows Brainstorm Brine Elemental Choking Tethers Coralhelm Guide Counterspell Court Hussar Curiosity Cursecatcher Dragon's Eye Savants Exclude Fathom Seer Flash Freed from the Real Genju of the Falls Ghost Ship Horseshoe Crab Jace, the Mind Sculptor Jalira, Master Polymorphist Man-o'-War Merfolk Looter Murder of Crows Mystic of the Hidden Way Pact of Negation Phantasmal Bear Reef Worm Retraction Helix Shoreline Ranger

Alandra, Sky Dreamer Alandra, Sky Dreamer can create tokens like some of the other draw a second card triggers, but this card has an even bigger draw payoff
Banned in Modern, this land says its time to tutor up some giant Eldrazi. I guess you could use this to tutor up Wandering Archaic or something for special cases, but really youll grab colorless ramp cards like Palladium Myr and Conduit of Ruin if this comes down early and then drop a titan whenever you can