Route 48: 17 species in 1 game

Road 48: 17 species across 2 versions

HeartGoldSoulSilver

HeartGold: 15 species
Species	Method	Levels	Chance	Game page
Fearow	Walking in tall grass or a cave	21	10%	All places
Gloom	Walking in tall grass or a cave	22 to 24	20%	All places
Diglett	Walking in tall grass or a cave	20	4%	All places
Growlithe	Walking in tall grass or a cave	21 to 25	up to 20%	All places
Farfetch’d	Walking in tall grass or a cave	25	up to 20%	All places
Exeggcute	Headbutting trees	15 to 18	up to 20%	All places
Tauros	Walking in tall grass or a cave	20 to 24	21%	All places
Hoothoot	Headbutting trees	15 to 18	up to 50%	All places
Spinarak	Headbutting trees	17 to 18	30%	All places
Hoppip	Walking in tall grass or a cave	20 to 22	up to 10%	All places
Girafarig	Walking in tall grass or a cave	20	5%	All places
Pineco	Headbutting trees	15 to 16	30%	All places
Plusle	Walking in tall grass or a cave	20 to 21	20%	All places
Minun	Walking in tall grass or a cave	22 to 24	20%	All places
Shinx	Walking in tall grass or a cave	20 to 24	40%	All places

SoulSilver: 15 species
Species	Method	Levels	Chance	Game page
Fearow	Walking in tall grass or a cave	21	10%	All places
Vulpix	Walking in tall grass or a cave	21 to 24	up to 20%	All places
Gloom	Walking in tall grass or a cave	22 to 24	20%	All places
Diglett	Walking in tall grass or a cave	20	4%	All places
Farfetch’d	Walking in tall grass or a cave	24	up to 20%	All places
Exeggcute	Headbutting trees	15 to 18	up to 20%	All places
Tauros	Walking in tall grass or a cave	20 to 24	21%	All places
Hoothoot	Headbutting trees	15 to 18	up to 50%	All places
Ledyba	Headbutting trees	17 to 18	30%	All places
Hoppip	Walking in tall grass or a cave	20 to 22	up to 10%	All places
Girafarig	Walking in tall grass or a cave	20	5%	All places
Pineco	Headbutting trees	15 to 16	30%	All places
Plusle	Walking in tall grass or a cave	20 to 21	20%	All places
Minun	Walking in tall grass or a cave	22 to 24	20%	All places
Shinx	Walking in tall grass or a cave	20 to 24	40%	All places