A dex is normally a lookup: you know the name, you want the numbers. This one is built for the other direction -- the whole set at once, as sprite chips washed in their primary type, so the type runs and the generation blocks show as bands from across the room.
Twenty-one sprite sets ship with it, Red/Blue through Scarlet/Violet, plus HOME renders and the animated sets. Coverage is genuinely patchy -- Red/Blue drew 151, FireRed re-drew 155, HOME covers 1336 -- so every gap is recorded and labelled rather than quietly filled in. The timeline view puts all 21 in one strip, because the drift from a 1996 Game Boy sprite to a 2024 render is a real thing nobody normally gets to look at.
Pick up to six and it answers the question a dex actually gets used for: what beats all of them at once? Behind that is a dashboard where every chart filters every other one -- power creep across nine generations, type effectiveness as a lens with a slider that lets you watch Gen 1's Ghost-does-nothing-to-Psychic bug get fixed, and type combinations by rarity.