All of these cards can easily go infinite or just massive
Unfortunately, the cards in this precon don't support the kind of deck manipulation needed to really get the most out of it and, where the likes of Brainstorm make for perfect setup, it only really has a handful of similar instants
Document everything with clear photos: the certification number, any signs of tampering on the case like cracks or a cloudy "frosting" effect, and any discrepancies between the card you received and the listing
Scales is one of the best ways to get additional counters onto creatures since it provides an extra counter each time a creature would get a +1/+1 counter
Retreat only costs 2 Energy if you need an easy getaway
However, if both Metagross and your opponents Pokemon have the same amount of Energy cards attached, it does 70 instead