With cards like Noctis, Prince of Lucis, capable of winning a match with a simple three-card combo, it's no wonder some of the rarest cards can fetch such a high price, even if some are likely to decrease in value over time
Summon: Shiva can also attack - but only gets to do so once, on the turn after she was played
Inks in Lorcana can be compared to mana colors from Magic: The Gathering or the various elements from Pokmon
Ryida, Summoner of Mist Fitting in with the limited theme of landfall for Red/Green Rydia rummages whenever you play a land, and can exploit that by hastily resurrecting the various summons in the set represented as enchantment creatures
They can also be put in your Inkwell if they aren't the card you're looking for at the time
They do not feature exclusive abilities or gameplay mechanics