If this Q&A was a test, that guy would most certainly fail.
How can he design Magic for a living?
They're called the 'Power 9' because in formats where they are legal,...
There is only ONE format where they are legal.
...most people believe you must have 1 of each of them (they are all restricted, so you can't have more) in any top deck.
Timetwister goes in ANY top deck from now on.
All of these cards appeared in the original Magic set, nicknamed 'Alpha.'
They also appeared in 'Beta' and 'Unlimited', but let's forget about that.
These cards are so powerful that games involving them often just come down to who draws theirs first.
Ha, I drew my Mox Emerald first, gg!
That's no fun, so Wizards doesn't print these cards anymore.
But if it were fun, Wizards would print them again, right?
That means they are very expensive and hard to find, so not many people play with them now.
Also, it's NO FUN. So even if they could find these EXPENSIVE cards and buy them, they wouldn't play with them.
But for people who still have these old cards, there's 'Type I' (also called Vintage), which is the format in which all kinds of old cards are legal, including the now all-but-legendary 'Power 9.'
Not all kinds of old cards are legal in T1. (Ante cards, etc)