Pokéblock Case appears in 3 version groups since Generation III, a Gameplay item in the Key Items pocket
PokéAPI item 532 of 2,223, Gameplay category, Key Items pocket
Effect, in PokéAPI's words
Pokéblock Case: “Holds Pokéblocks.”
Stores Pokéblocks.
Games
Pokéblock Case is listed in the text of 3 version groups, first in Generation III
Game index by generation
IIIIIIIVVVIVIIVIIIIX
Named in
Ruby and SapphireEmeraldFireRed and LeafGreen