Promise of the World Legacy
When this card is activated: You can Set 1 "World Legacy" Spell/Trap directly from your Deck. That Set card can be activated during this turn. Reduce the Level of all "World Legacy" monsters in your hand by 1. You can only activate 1 "Promise of the World Legacy" per turn.
IDK what Konami has planned for World Legacy, but I noticed that Armor likes to be Normal Summoned, but it's 1 Level away from requiring 1 Tribute, while Chalice is 1 Level away from being Normal Summonable without Tributes; meanwhile, they already got plenty of Spell/Traps that are unique in that they support their respective archetypes, World Legacy cards themselves (e.g. Beacon, Trap Crawling) and even a generic one (e.g. Battle for the World Legacy). So, I figured they would appreciate a card that reduced the Levels of their monsters by 1, plus I added a searching effect for the value and to not make the card a mere Continuous effect that doesn't give any advantage on its own, also to take advantage of that interesting variety of Spell/Traps they have. However, rather than going for a cookie-cutter "add it to your hand", I decided to go for a clause that conveniently lets them activate their World Legacy Traps without waiting for a turn.