Berry Forest: 20 species in 1 game

20 species, 2 versions

FireRed and LeafGreen

FireRed and LeafGreen: 16 species
Species	Method	Levels	Chance	Game page
Pidgey	Walking in tall grass or a cave	32	10%	All places
Pidgeotto	Walking in tall grass or a cave	37	20%	All places
Oddish	Walking in tall grass or a cave	30	10%	All places
Gloom	Walking in tall grass or a cave	35	20%	All places
Venonat	Walking in tall grass or a cave	34	10%	All places
Venomoth	Walking in tall grass or a cave	37 to 40	5%	All places
Psyduck	Fishing with a super rod	15 to 35	5%	All places
Psyduck	Surfing	5 to 40	95%	All places
Psyduck	Walking in tall grass or a cave	31	5%	All places
Golduck	Surfing	35 to 40	5%	All places
Poliwag	Fishing with a good rod	5 to 15	20%	All places
Drowzee	Walking in tall grass or a cave	34	10%	All places
Hypno	Static encounter	30	100%	All places
Hypno	Walking in tall grass or a cave	37 to 40	5%	All places
Exeggcute	Walking in tall grass or a cave	35	5%	All places
Goldeen	Fishing with a good rod	5 to 15	60%	All places
Goldeen	Fishing with a super rod	15 to 25	40%	All places
Seaking	Fishing with a super rod	20 to 30	40%	All places
Magikarp	Fishing with a good rod	5 to 15	20%	All places
Magikarp	Fishing with an old rod	5	100%	All places
Gyarados	Fishing with a super rod	15 to 25	15%	All places