Hoenn
Route 103 (grass above oldale, west of water)
Pickup: Pokeball, Potion, Repel, Plain Bitter Seed, Plain Sour Seed, Plain Spicy Seed, Plain Sweet Seed, Plain Dry Seed
Trainer Pick:Pokeball, Potion, Plain Sour Seed, Plain Spicy Seed, Plain Sweet Seed, Plain Dry Seed
Numbers in Spoiler
Tested with 216 504 encounters. will update if more are found