As mentioned, some of the ones that collectors are always on the look for are what are called V and EX cards, which are full art displays of the featured Pokemon
While its base typing doesn't include Dragon, Mega Charizard X gained the Dragon typing on its debut, finally placing this iconic Pokemon among the dragon peers it has visually mimicked for so many years
This deck revolves around fast artifact mana through Urza, which it uses to rush out stax pieces and eventually combo off by using a Polymorph on your Construct token
Sorry we can't be more precise, but there's really no 'best Pokmon set' that applies to everyone
Nostalgia is kingGen 7 and older sets like Bandai Carddass are surging, with Charizard prisms up 30% on speculation of special box sets
The best choice for you will depend on the cards you have to sell, and how much prep work you're willing to do