This sort of trick can make or break Commander games, especially if one were to place it atop an Isochron Scepter
Ancient Copper Dragon isn't as beloved/reviled as Rhystic Study, but that's mainly because, unlike Rhystic Study, it hasn't existed for 25 years
Friendly Teddy is a 2/2 that simply allows each player to draw an extra card when it dies, which is pretty friendly I guess
11 Yarok, The Desecrated Double The Atrocities Enters-the-battlefield triggers are the deep wells within which much of the power in modern Magic cards can be found, which is why Yarok, who lets you double down on said effects, is such a powerful Horror in Commander
Per Pokmons official announcement of The Pokmon Trading Card Game Classic, no cards contained within this product will be legal for tournament play, except for the products basic energy cards