Sadly, Ho-Oh, as well as Lugia, Deoxys, Jirachi, Mew and Celebi, are event Pokemon. This means that, unless you are lucky enough for a Ho-Oh give out event to pass near your town, you will have to get it by trade or pokesav.
http://www.psypokes.com/lab/shiny.php
You can catch Lugia at Navel Rock.
It is not possible to catch Mew is Pokémon Emerald version without using cheats. The only way to get it would be to trade.
simple answer: there´s NONE
No you can't catch deoxys by using cheats
Catch it in firered or leafgreen, then migrate.
you cant catch any starter without picking it as your first pkmn or using a code to get the one you don't have
Don't use cheats. They will mess your game up. I always play without using cheats so it doesn't mess up my game.
there was an event at toys-r-us but its over so no you cant catch him anymore without cheats or action replay
You have to upload it from FireRed, LeafGreen, Ruby, Sapphire, or Emerald.
you cant only by using cheats
Here is the answer to your questionYou can catch all Pokemon on leafgreen by using Pokeballs to catch them after you battle them. Why don't you not be lazy and just catch them for yourself instead of using cheat codes when you do not feel like catching them.