Pick a ROM hack or official game to build with its own Pokémon, moves and boss fights, or build from every official Pokémon. Add up to six, pick each one's moves from what it can learn, and see what the team resists, what it is weak to and what its moves cover. Every number comes from the game's own documentation, or from the official Pokédex when no game is picked.
With no game picked the page uses the official National Pokédex. Choose one and a Pokémon only appears if that guide has it, because its typing, spread and abilities are that game's. “By this point in the game” reads the guide's own encounter tables, so it shows what that game lets you catch by then and nothing else. A moveset is drawn from the game's own level-up, TM, tutor and egg-move data, so a game that never published one of those four simply offers fewer moves to choose from. On a game with types outside the standard eighteen, the coverage tables count only the types the chart knows.