Where are the other four
and a double-sided card featuring a European Swallow on one side and African Swallow on the other
K type card and add it to your hand
You can do what you want with the data from here
Choosing which ones to put in your deck and which to leave in your sideboard (any cards that you don't play in your main deck automatically make up your sideboard in Limited) is one of the big skills in Limited

Erase (Not the Urza's Legacy One) Glasses of Urza Karn, Scion of Urza Liberator, Urza's Battlethopter Sunglasses of Urza Tawnos, Urza's Apprentice Urza Urza Assembles the Titans Urza's Armor Urza's Avenger Urza's Bauble Urza's Blueprints Urza's Cave Urza's Chalice Urza's Command Urza's Contact Lenses Urza's Dark Cannonball Urza's Engine Urza's Factory Urza's Filter Urza's Fun House Urza's Guilt Urza's Hot Tub Urza's Incubator Urza's Mine Urza's Miter Urza's Power Plant Urza's Rage Urza's Rebuff Urza's Ruinous Blast Urza's Saga Urza's Science Fair Project Urza's Sylex Urza's Tome Urza's Tower Urza's Workshop Urza, Academy Headmaster Urza, Chief Artificer Urza, Lord High Artificer Urza, Lord High Artificer Urza, Lord Protector Urza, Planeswalker Urza, Powerstone Prodigy Urza, Prince of Kroog