You can get a vague idea of the types of cards in each pack by the stats shown on the pack preview screen, though vague is key here
In the episode, Pegasus sucks Yugi into the TV as he steals his grandfather's soul, and plays the Eye of Illusion card to take control of Yugi's Dark Magician too
Nantuko Monastery Compare the rate on Nantuko Monastery to the Forgotten Realms manlands and it comes out decent, I think
The formats been harsh to control decks, but never enough to leave Teferi totally out
A good example is Hollow One dealing with Humans via Grim Lavamancer and Engineered Explosives
There are a few different factors which will determine how you can price your cards on the market, including condition, if its a set, rarity, and overall demand