Route 18: 10 species in 1 game

Road 18: 10 species across 2 versions

X and Y

X and Y: 9 species
Species	Method	Levels	Chance	Game page
Sandslash	Walking in red flowers	44 to 45	20%	All places
Sandslash	Walking in tall grass or a cave	46	10%	All places
Geodude	Encountering 5 pokemon within grass, flowers, or within a cave	23	60%	All places
Graveler	Walking in red flowers	45 to 46	15%	All places
Graveler	Smashing rocks	44 to 46	95%	All places
Graveler	Walking in tall grass or a cave	45 to 46	15%	All places
Shuckle	Smashing rocks	44 to 46	5%	All places
Lairon	Walking in red flowers	44 to 46	30%	All places
Lairon	Walking in tall grass or a cave	46	10%	All places
Torkoal	Walking in red flowers	46	10%	All places
Torkoal	Walking in tall grass or a cave	44 to 45	20%	All places
Gurdurr	Walking in red flowers	46	10%	All places
Gurdurr	Walking in tall grass or a cave	44 to 46	30%	All places
Heatmor	Encountering 5 pokemon within grass, flowers, or within a cave	23	5%	All places
Heatmor	Walking in red flowers	45 to 46	5%	All places
Heatmor	Ambushed by a wild pokemon from a rustling bush	45	10%	All places
Heatmor	Walking in tall grass or a cave	45 to 46	5%	All places
Durant	Encountering 5 pokemon within grass, flowers, or within a cave	23	40%	All places
Durant	Walking in red flowers	44	10%	All places
Durant	Ambushed by a wild pokemon from a rustling bush	44 to 46	90%	All places
Durant	Walking in tall grass or a cave	44	10%	All places