Cards tied to prizes, contests, and promotional events tend to be the scarcest, because they were never meant for mass distribution in the first place
A fourth one that I collected when young was Digimon, which didn't take off at the time of original release nor with its subsequent attempts to launch in the west until this last year which saw the release of their latest simply titled Digimon Card Game
Ritual Summoning In order to perform a Ritual Summon, you need a card or Effect that allows you to do so, usually a Ritual Spell
C Common Valkyrie of the Nordic Ascendant X LIGHT Level 2 [ FairyTunerEffect ] ATK 400 DEF 800 (This card is not treated as a "Valkyrie" card.) When this card is Normal Summoned, if your opponent controls a monster and you control no other cards: You can banish 2 "Nordic" monsters from your hand
Vintage and crossover cards From vintage stars to modern pop-culture inserts, collectors apply the same protection approach to any sports-related card with age, scarcity, or resale value
Questions Key Card Sleeves & Holders, answered What information can we print on a key card sleeve