To get the best price on specific Pokmon cards, visiting specialist trading card sites such as TCGplayer and Magic Madhouse is often best, as well as checking in your local game store - as they often have their own way of checking a cards authenticity, and rely on their reputation among knowledgeable fans for business
If you hold them up to the light, you'll see that they glisten beautifullymuch like the scales of a salmon as it careers through the air after getting absolutely catapulted out of a river by the powerful forepaws of a hungry bear
Goblins, humans, and warriors look doable, and you could probably cross creature types (e.g goblin rabblemaster)
If the card put into your graveyard is an instant or sorcery card, Aberrant Researcher will have transformed before a player can take any action
What makes this card so difficult to read is the layering of the colors