Kk today i am going to tell you how to get your starters and lengedary pokemon like mewtwo, moltres, zapdos,articuno the're are more but i am not going to say all the lengedary kk, so let's get started with it shall we?
for starters:
well before you chose a starter save in front of the pokeball you want to pick, then chose the pokemon say charmender, go to summary and check if the sprite has got a glod star in it's right upper corner if not turn off your gameboy and turn it on again and do what i said but do not save again kk i know it will take alot of time but you can also use action replay or gameshark but i am saying this to you because you can get bad eggs that can ruin your game.
for lengedary pokemon:
before you battke the pokemon save in front of it, then battle it if it glows some stars when the battle begins and has a different color then congratulation you have a shiny lengedary pokemon, it will probaly take alot of time but as i said you can use cheats to make every pokemon in your game shiny, anyway continuing to explaining welll if it isn't shiny turn off your gameboy and turn it back on but do not save save only one time so you can turn off your gameboy or else you won't be able to catch the pokemon in shiny version kk.

happy catching believe i know it is very hard to get one and you have to keep turning off and on your gameboy and checking the pokemon to see if it is shiny but it is worth it kk because you may have friends that collect shiny pokemon and you can trade them shiny starters or legendary pokemon to get other pokemon you don't have and that you can't catch in the game o complete the pokedex. !!Piece!!