This can be seen with FF2 's Firion, and in the case of FF9 , Zidane Tribal can be found in booster packs as Ragavan, Nimble Pilferer, a popular card in Magic: The Gathering 's Modern and other formats, too
Whenever you cast a black spell, put a +1/+1 counter on Emet-Selch
Completing a dungeon will also allow specific ability text on other cards to be used, with Gloom Stalker and the very meta Dungeon Crawler revealed as two such cards that gain benefits from a completed dungeon - double strike and the option to return to the player's hand from the graveyard respectively
Based on context, there's a chance the term "challenge" is a less confrontational version of battling or attacking an enemy card
Well, it does the things we need, which is why we have it as a commander and why were playing a card where we can have any number of copies