Seal Case appears in 10 version groups since Generation IV, a Gameplay item in the Key Items pocket
PokéAPI item 411 of 2,223, Gameplay category, Key Items pocket
Effect, in PokéAPI's words
Seal Case: “Stores Seals that can be applied to Poké Ball capsules.”
Contains Seals used for decorating Pokéballs.
Games
Seal Case is listed in the text of 10 version groups, first in Generation IV
Game index by generation
IIIIIIIVVVIVIIVIIIIX
Named in
Diamond and PearlPlatinumHeartGold and SoulSilverBlack and WhiteBlack 2 and White 2X and YSun and MoonUltra Sun and Ultra MoonLet's Go Pikachu and Let's Go EeveeSword and Shield