Defeat Mura in Tim's Lab
Defeat Mura in Hayward City
Defeat Mura in Haunted Forest
Earn Marine Badge in Merson City
Earn Hail Badge in Owsauri City
Earn Sparky Badge in Jaeru City
Earn Sprout Badge in Moraga Town
Earn Fist Badge in Castro Valley
Find Porygon in Route 55
Defeat Giovanni in Silph Co. Warehouse
Trade Abra for Magmar in Route 52 House (if you don't own Magmar)
Trade Clefairy for Lapras in Hayward City
Trade Shellder for Rhyhorn in Route 49 House (if you don't own Rhyhorn)
Trade Nidoqueen for Nidoking in Moraga Town House
Trade Pidgey for Chansey in Castro Valley (if you don't own Chansey)
Catch Kangaskhan in Haunted Forest
Catch Snorlax on Route 61
Catch Raikou or Zapdos in Power Plant
Earn PSI Badge in Seashore City
Earn White Badge in Castro Forest
Defeat Bug Catcher in Azalea Town
Earn Star Badge in Eagulou City
Get Omanyte in Hayward City
Catch Entei or Moltres in Cave on Route 53
Catch Suicune or Articuno in Mt.Boulder
Trade Gligar for Eevee in Botan City (if you don't own Eevee)
Trade Butterfree for Tyrogue in Botan City (if you don't own Tyrogue)
Buy Jigglypuff in Poke Center (Route 67 behind Seneca Cavern)
Catch Mewtwo or Mew in Secret Cave
Beat the Elite Four and the Champion of the Rijon League
Beat the Elite Four and the Champion of the Rijon League with only one Pokemon in your party
Get the Pokemon in Slot 1 from Level 99 to Level 100
Assemble a full team of Pokemon in your party
Trade Rhyhorn for Crobat in Unknown Cave (if you don't own Crobat)
Find Ho-Oh or Lugia in Unknown Cave
Defeat Patrol Pallet in Unknown Cave
Get Kabuto in Hayward City
Get Cranidos in Hayward City
Defeat Patrol Pallet in Unknown Cave with only one Pokemon in your party
Catch 210 Pokemon without external trading