Of course, graded PSA 10 slabs of Legendary Collection cards are eminently hard to come by, since many young collectors at the time didnt even understand just how rare such cards were (myself included)
In a split second, your creatures can die, your artifacts can be shattered, and your opponent can win the game
While there are plenty of solid Rockets Pokemon (as youve seen), it makes it a little difficult to use any of the very powerful supporting Pokemon available to other decks
Have fun!
Note: Foils are a special case, since they represent higher levels of rarity vs the non-foil version, but are much more desirable in some formats (Vintage, Legacy, Modern, EDH), than in others (Standard, Casual)
The first thing thats good about the engine is it in general can help make a deck more consistent