Urza, Lord High Artificer (Retro) [Dominaria Remastered] BT16-147 you can activate it by

you can activate it by paying its energy cost and removing it and 1 yellow card in your hand from the game

Copper Tablet deals 1 damage to that player

Before any major undertaking

If it's a permanent spell

000 Type: Creature — Tyranid Rarity: Rare Cost: {X}{3}{G} Ravenous (This creature enters the battlefield with X +1/+1 counters on it

Urza, Lord High Artificer (Retro) [Dominaria Remastered] BT16-147 you can activate it bySet: Dominaria Remastered Type: Legendary Creature Human Artificer Rarity: Mythic Cost: {2}{U}{U} When Urza, Lord High Artificer enters the battlefield, create a 0 0 colorless Construct artifact creature token with "This creature gets +1 +1 for each artifact you control." Tap an untapped artifact you control: Add {U}. {5}: Shuffle your library, then exile the top card. Until end of turn, you may play that card without paying its mana cost.