You'll get 8 standard packs of cards (just like you'd get in a booster box), 65 card sleeves (the Eternatus sleeve you see above), 45 energy cards, 6 damage-counter dice, 2 acrylic condition markers, a code card for the digital game, 1 competition-legal coin-flip die, and a Pokemon TCG rulebook
Card Size is Different Paper Quality difference and Paper Thickness, but this depends on the set too I think, because they may change the paper stock that they use depending on cost of materials you can also ask a Pokemon Professor, they may have insight into fake cards entering the market and be able to give you pointers in spotting fakes
A 25-Dragon deck is probably quite excessive
Close up Part 1
This is the Arcanine Pokemon 1999 Base Set English 23/102 NM Pokemon Card that comes in very good condition
Wayfaring Temple, Voice of Resurgence, Geist-Honored Monk, and Adeline, Resplendent Cathar are all staple cards for this ability