As @toysaver , wrote you need to do your own research, especially on collectible items. A good place to start would be to buy a Gaming card price guide book.
Most of those guides will explain the differences between foil, lenticular and hologram (Holo) cards. Becketts Gaming Card price guide.
While price guides tend to list the higher realized prices, that may or may not be relevant to ebay sales, they are full of information including
on how grade cards and to spot counterfeited ones.
You can also do an advanced search > Completed listings > Pokemon game cards you can add Character name and other info.
Results in green are items that sold those in black did not. You may want to check the results between Auction and Buy It now formats.
Many collectibles sell for better prices if you auction them.