The number of cards is a bit irregular, but basically it's 1 card with other creatures, and sometimes 2 cards if there's an artifact
Duplicates in Pokemon TCG Pocket can be turned into Flair, which gives cards an animation when theyre played on the field
Chimney Imp is bad enough to make this list (a 1/2 flyer for five mana is really below rate), but it gives you card advantage (usually) when it dies
There is a huge difference in market value of a grade 9 vs a grade 10
This legendary creatures proliferate ability works especially well with planeswalkers, as you can put extra loyalty counters on each of them at the end of every turn
Crusty Games also has a The Ur-Dragon deck (here's our guide on The Ur-Dragon) listed for over $155, and again, doesnt tell you what cards youre guaranteed to get