Anno'un Music:
While in the Alpha Ruins south east of Kikyou city go to the Pokégear option in the menu screen. Go to the radio option and on the fourteenth to the twentieth channel you can find a station Called ??????. That is the Ann'oun Music. It can only be heard at Alpha Ruins. 

Buruki:
In the town with the fourth gym, go inside the second cave and turn to the right and SURF. Go to the top and enter another cave that is there. Make your way around  the mazes and talk to the karate character that is there. Defeat him and you will get Buruki. Note: Make sure you have an open space in your Pokemon holder. 

Breeding evolutions:
Breed two Pikachus to get Pichu. 
Breed two Electabuzzes and you get Eleckid. 
Breed two Clefairies and you get Pi. 
Breed two Jigglypuffs and you get Pipurin. 
Breed two Magmars and you get Magar. 

Enjyu City battle (Gold version):
When you go to Enjyu City, go to the tower and your rival will appear, but will not battle. However, if you first heal your Pokemon at the Pokemon Center, defeat the Ghost Gym Leader, and then go to that tower, your rival will talk to you and fights. 

Female Mr. Mime (Gold version):
Go to Saffron City before fighting Sabrina. Challenge Sabrina to discover that her Mr. Mime is female. 

Gym Leader tactics (Gold version):
Use the following Pokemon types to battle the indicated Gym Leaders. 

Hayato (for Wind Badge) 
Pidgey: Use Electric type 
Pidgeotto: Use Electric type 

Unknown (for Insect Badge) 
Metapod: Use Fire type 
Kakuna: Use Fire type 
Scyther: Use Fire type 

Akane (for Normal Badge) 
Clefairy: Use Psychic type 
Mirutanku: Use Psychic type 

Unknown (for Phantom Badge) 
Ghastly: Use Psychic type 
Haunter: Use Psychic type 
Gengar: Use Psychic type 
Haunter: Use Psychic type 
Unknown (for Shock Badge) 
Primeape: Use Psychic type 
Poliwrath: Use Grass type 

Mikan (for Steel Badge) 
Magnemite: Use Fighting type 
Magnemite: Use Fighting type 
Haganail: Use Fighting type 
Unknown (for Ice Badge) 
Seel: Use Electric type 
Dewgong: Use Electric type 
Inomu: Use Electric type 

Ibuki (for Raging Badge) 
Dragonair: Use Fire type 
Dragonair: Use Fire type 
Kingudora: Use Fire type 
Dragonite: Use Fire type 

Lt. Surge (for Orange Badge) 
Raichu: Use Fighting type 
Magneton: Use Fighting type 
Electabuzz: Use Fighting type 
Electrode: Use Fighting type 
Electrode: Use Fighting type 

Sabrina (for Gold Badge) 
Mr.Mime: Use Psychic type 
Alakazam: Use Psychic type 
Eifi: Use Psychic type 
Erika (for Rainbow Badge) 
Tangela: Use Fire type 
Victreebell: Use Fire type 
Vileplume: Use Fire type 

Anzu
Kurobatto: Use Psychic or Fire type 
Ariadosu: Use Psychic or Fire type 
Weezing: Use Psychic type 
Weezing: Use Psychic type 
Venomoth: Use Fire type 

Brock
Graveler: Use Grass type 
Onix: Use Grass type 
Rhyhorn: Use Grass type 
Omastar: Use Grass type 
Kabutops: Use Grass type 
Blane (for ?) 
Magakarugo: Use Water type 
Rapidash: Use Water type 
Magmar: Use Water type 

Gary
Pidgeot: Use Electric type 
Alakazam: Use Psychic type 
Exeguttor: Use Fire type 
Rhydon: Use Grass type 
Arcanine: Use Water type 

Ash Ketchum (Final battle for bragging rights) 
Pikachu: Use Fighting type 
Efi: Use Psychic type 
Blastiose: Use Electric type 
Venusaur: Use Fire type 
Charizard: Use Water type 
Snorlax: Use Fighting type 

Gold Gyarados:
Go to the fourth gym and SURF right all the way. You will SURF in the water should see a Gyarados. Battle it, and it will be golden. 

Gold Magikarp:
Breed the golden Gyarados with a regular Gyarados to get a golden Magikarp. 

Haganal:
Equip the Metal Coat on Onix and trade it to another GameBoy. It will evolve into Haganal. 

Hou-Hou (Gold version):
Go to the city with the fourth gym. Go inside the house with another house beside it. Climb up and enter the other big house. Climb up until you get to Hou-Hou. 

Hou-Hou (Silver version): 
Go to Pewter City and talk to the old man that walks around. He will give you a gold feather. Now, go to the place where Hou-Hou is located in the Gold version to find it. 

Lapras:
Enter the cave in the second city and SURF. You should be able to see Lapras.  Note: There is only one. 

Lugia (Silver version):
Learn HM06 (Whirlpool) and go to the place where you received the fifth badge.Destroy a whirlpoor and enter the cave. Go through the maze and you will reach Lugia. 

Lugia (Gold version):
Go to Pewter City and talk to the old man. He will give you a silver feather. Now, go to the place where Lugia is located in the Gold version to find it.. 

Monorail ticket:
Go to Saffron City and talk to the girl copy cat. FLY to Vermilion City and talk to everyone in the house where you received the bike voucher. Someone will give you 
the Clefairy doll. Take it to the copycat and to get the monorail ticket. 

Starting Pokemon (Gold version):
-Select one of the following to get your first Pokemon. 
Chicorita: a Grass type, like Bulbasaur. 
Waninoko: a Water type, like Squirtle. 
Hinorashi: a Fire type, like Charmander. 

Silver Ryhorn:
Go to the cave where you go to get to the Elite Five. You should encounter a silver Ryhorn. 

Three legendary dogs:
Go to the city with the fourth gym and enter the big house. Break the rocks and fall down one of the holes to wake them up. Then, just go outside and try to find them in the wild. 

Togepi:
Defeat the first gym and go into the Pokecenter. Talk to the scientist and he will give you a egg. After 5,000 steps, it will hatch into Togepi. 

Yadoking:
Equip Symbol Of King on Slowpoke and trade it into another GameBoy. It will evolve into Yadoking. 

Orange League Trainer tactics (Gold version):
Use the following Pokemon types to battle the indicated Trainer. 

Itkusi
Neiteio: Use Psychic or Fire type 
Slowbro: Use Psychic type 
Neiteio: Use Psychic or Fire type 
Jynx: Use Psychic type 
Exeggutor: Use Fire type 

Koga
Araidosu: Use Psychic or Fire type 
Venomoth: Use Fire type 
Muk: Use Psychic type 
Kuroba: Use Psychic or Fire type 
Fuoretosu: Use Psychic or Fire type 

Bruno
Kaporea: Use Psychic or Grass type 
Hitmonchan: Use Psychic type 
Hitmonlee: Use Psychic type 
Machamp: Use Psychic type 
Onix: Use Grass type 

Karin 
Burakki: Use Psychic or Fire type 
Vileplume: Use Fire type 
Gengar: Use Psychic type 
Yamikarasu: Use Psychic or Fire type 
Heruga: Use Psychic or Fire type 

Lance
Gyrados: Use Grass type 
Dragonite: Use Electric type 
Dragonite: Use Electric type 
Dragonite: Use Electric type 
Aerodactyl: Use Grass type 
Charizard: Use Water type