Trophy Garden: 22 species in 2 games

22 species, 3 versions

Diamond and PearlPlatinum

Diamond and Pearl: 21 species, all by walking in tall grass or a cave
Species	Levels	Chance	Game page
Pikachu	18	up to 5%	All places
Clefairy	16 to 18	10%	All places
Jigglypuff	16 to 18	10%	All places
Meowth	16 to 18	10%	All places
Chansey	16 to 18	10%	All places
Eevee	16 to 18	10%	All places
Porygon	16 to 18	10%	All places
Pichu	16	up to 20%	All places
Cleffa	16 to 18	10%	All places
Igglybuff	16 to 18	10%	All places
Marill	16 to 18	10%	All places
Azurill	16 to 18	10%	All places
Plusle	16 to 18	10%	All places
Minun	16 to 18	10%	All places
Roselia	16 to 17	30%	All places
Castform	16 to 18	10%	All places
Staravia	16 to 17	up to 20%	All places
Kricketune	16 to 17	up to 20%	All places
Bonsly	16 to 18	10%	All places
Mime Jr.	16 to 18	10%	All places
Happiny	16 to 18	10%	All places

Platinum: 21 species, all by walking in tall grass or a cave
Species	Levels	Chance	Game page
Pikachu	22 to 24	up to 5%	All places
Clefairy	22	10%	All places
Jigglypuff	22	10%	All places
Meowth	22	10%	All places
Chansey	22	10%	All places
Ditto	22	10%	All places
Eevee	22	10%	All places
Pichu	21 to 22	up to 25%	All places
Cleffa	22	10%	All places
Igglybuff	22	10%	All places
Marill	22	10%	All places
Azurill	22	10%	All places
Plusle	22	10%	All places
Minun	22	10%	All places
Roselia	22 to 23	30%	All places
Castform	22	10%	All places
Staravia	22 to 24	up to 20%	All places
Kricketune	22 to 23	up to 20%	All places
Bonsly	22	10%	All places
Mime Jr.	22	10%	All places
Happiny	22	10%	All places